[Expression of alpha-SMA mRNA in the lung tissue of rat with asthma]

OBJECTIVE

To investigate the expression of smooth muscle actin(SMA)-alpha mRNA in the lung of rat with asthma.

METHODS

A rat model of asthma was established by exposing the animal to aerosolized ovalbumin (OA). After being sensitized, the rat was subjected to laboratory tests. alpha-SMA mRNA of the lung tissue was measured by RT-PCR. The thickness of the airway smooth muscle(ASM) was measured by an image analysis system at the same time.

RESULTS

The thickness of ASM increased 2 weeks after OA challenge. The expression of alpha-SMA mRNA increased 1 week after OA challenge and increased more significantly after 2 weeks.

CONCLUSION

In the rat model of asthma, hypertrophy and hyperplasia of the airway smooth muscle were noted, and the phenotype was changed.

[Bone marrow-derived CD+34 cells expressing interleukin-5 receptor messenger RNA and asthmatic airway inflammation]

OBJECTIVE

To study the possible role of bone marrow-derived hematopoietic cells expressing CD(34)(+) and IL-5 receptor messenger RNA (IL-5R mRNA(+)) in asthmatic airway inflammation.

METHODS

Balb/c mice were sensitized and challenged by ovalbumin (OVA) to establish the asthmatic model. The control mice were sensitized and exposed to sterile saline. The mice were killed at different time points after challenged by OVA and sterile saline, and bronchoalveolar lavage (BALF), peripheral blood (PB) and bone marrow (BM) were prepared. Eosinophils (EOS) in PB and BALF, and nuclear cells in PB and BM were counted. The percentage of CD(34)(+) cells to nuclear cells (CD(34)(+)%) in PB and BM, and the relative number of CD(34)(+) cells (CD(34)(+)) in PB and BM were calculated by flow cytometry. Immunocytochemistry and in situ hybridization were used to observe the hematopoietic cells with co-localized expression of CD34 and IL-5R mRNA (CD(34)(+)/IL-5R mRNA(+)) in BM. The percentage of BM CD(34)(+)/IL-5R mRNA(+) to BM CD(34)(+) was calculated.

RESULTS

(1) At 6 h after OVA challenge, the number of BALF EOS [(2.67 +/- 1.00) x 105/L] was significantly increased as compared to the number in controls [(0.46 +/- 0.06) x 105/L] (P < 0.01). At 12 h after OVA-challenge, the numbers of BALF EOS [(7.74 +/- 1.98) x 105/L] and PB EOS [(2.91 +/- 0.64) x 108/L] were significantly higher than those in the controls (P < 0.01). At 24 h after OVA-challenge, the numbers of BALF EOS[(19.43 +/- 3.69) x 105/L], PB EOS[(3.93 +/- 0.51) x 108/L] and BM CD(34)(+)/IL-5R mRNA(+) [(300.50 +/- 90.02) per thousand] were increased to the highest levels. The differences were significant as compared to the corresponding parameters in the controls (P < 0.01). At 48 h after OVA-challenge, the numbers of BALF EOS [(12.05 +/- 5.31) x 105/L] and BM CD(34)(+)/IL-5R mRNA(+) [(220.80 +/- 53.41) per thousand] were decreased, but were still significantly different compared to the numbers in the controls (P < 0.01), while other markers returned to the normal levels. (2) The number of BM CD(34)(+)/IL-5R mRNA(+) in the 60 mice was closely correlated with BALF EOS, PB EOS, BM CD(34)(+) and BM CD(34)(+) (P < 0.05).

CONCLUSION

CD(34)(+) cells expressing IL-5R mRNA, which may favor eosinophilopoiesis and eosinophilic airway inflammation, were increased in the BM of this mouse asthmatic model. A feedback mechanism between the lungs and the bone marrow likely exists, which may be involved in the development and persistence of asthmatic airway inflammation.

[Effect of montelukast on the apoptosis of lymphocytes in asthmatic rats and its molecular mechanism]

OBJECTIVE

To investigate the effect of montelukast(MK) on the apoptosis of lymphocytes and the associated molecular mechanism in asthmatic rats in vivo and in vitro.

METHODS

The asthmatic model was established by sensitizing and challenging SD rat with ovalbumin (OVA). Forty male SD rats were randomly divided into control group, asthma group, MK-treated group and Dexamethason (DXM)-treated group. T lymphocytes were labeled with CD(4)+ and CD(8)+ antibodies and then labeled with TdT-mediated dUTP nick end labeling (TUNEL) to detect apoptotic cells, and immunohistochemical staining of Fas antigen (CD95) was performed to detect Fas positive cells. The influences of MK on apoptosis and Fas antigen spontaneous expression on CD(4)+ / CD(8)+ lymphocytes in vivo and in vitro were assayed.

RESULTS

The apoptosis rates of T lymphocytes from peripheral blood and lung tissue of asthmatic rats pre-treated by MK were significantly elevated as compared with those in normal control and asthma groups. In vitro culture MK was found to induce in dose- and time-dependent manner the apoptosis of peripheral blood lymphocytes pre-treated with OVA. A synergic effect of MK and DXM was demonstrated, i.e. MK in 10(-6) mol/L concentration markedly promoted the induction of apoptosis and expression of Fas antigen by 10(-6) mol/L DXM.

CONCLUSION

MK could induce apoptosis of peripheral blood and lung lymphocytes (mainly CD(4)+) in asthmatic rats, which may be mediated by Fas system. The induction of apoptosis of lymphocytes by MK may contribute to anti-inflammation mechanisms. Furthermore, a synergic effect of MK and DXM on the induction of apoptosis of lymphocytes might exist.

[Effect of budesonide on Clara cell secretory protein and its mRNA expression in a rat model of asthma]

OBJECTIVE

To investigate the effect of inhaled glucocorticoids on the expression of Clara cell secretory protein (CCSP) and its mRNA in lung tissue of a rat model of asthma.

METHODS

The rat asthmatic model was established by sensitizing and challenging SD rats with aerosolized ovalbumin (OVA). Rats were divided into a control, an asthmatic and a glucocorticoid groups. Budesonide aerosol was delivered by a jet nebulizer. The CCSP mRNA level in the lung tissue and the CCSP level in bronchoalveolar lavage fluid (BALF) were determined by RT-PCR and dot immuno-blotting, respectively.

RESULTS

The level of CCSP mRNA in the lung tissue was 0.65 +/- 0.04 in the control, 0.56 +/- 0.05 in the asthmatic and 0.63 +/- 0.04 in the glucocorticoid groups, respectively (asthma versus control, P < 0.01; glucocorticoid versus asthma, P < 0.05). The CCSP level in BALF was 60 +/- 5 in the control, 49 +/- 5 in the asthmatic and 57 +/- 5 in the glucocorticoid groups, respectively (asthma versus control, P < 0.01; glucocorticoid versus asthma, P < 0.05). Budesonide reduced the percentage of eosinophils in BALF and inhibited airway inflammation.

CONCLUSIONS

OVA challenge in the rat model decreased CCSP mRNA, resulting in a reduction in CCSP production, which may contribute to asthmatic airway inflammation. Inhaled glucocorticoids increased the expression of CCSP mRNA in lung tissue, which may be a mechanism for the suppression of airway inflammation by glucocorticoids.

Sharing patient care records over the World Wide Web

In order to obtain appropriate medical care, patients can be referred or transported from one hospital to another based on the capacity, capability and quality of medical care provided by hospitals. Therefore, enabling patient care records to be shared among hospitals is essential not only in delivering the quality of medical care services but also in saving medical expenses. Currently, most patient care records are paper-based and not well organized. Hence, they are usually incomplete and can hardly be accessed in time. The authors in this paper present methods to structure and represent patient care records, design mechanisms for interpreting and integrating the XML-based patient care records into the existing hospital information systems. More importantly, in our approach, each significant piece of medical record is associated with a tag based on the syntax and semantics of the XML. The XML-based medical records enable a computer to capture the meaning and structure of the document on the web. The authors have developed a unified referral information system in which patient care records can be shared among hospitals over the Internet. It can not only facilitate the referral process but also maintain the integrity of a patient's medical record from distributed hospitals. The workflow of the system basically follows the existing manual system and can easily be adapted. The working group on integration of municipal hospital information systems, Department of Health, Taipei City Government, has decided to adapt this system for referral practice among the municipal hospitals.

Building a generic architecture for medical information exchange among healthcare providers

Due to the inability to exchange clinical information among hospitals, continuity of care cannot be maintained and a tremendous amount of medical resource has been wasted. This paper describes an architecture that would facilitate exchange of clinical information among heterogeneous hospital information systems. It is dubbed 'Medical Information Exchange Center' or MIEC as part of a six-year Health Information Network Project hosted by the Department of Health. MIEC was designed so that it is innovative yet technically feasible today. It is convenient for authorized users yet secure enough so people can trust and has minimal impact to participated hospitals. Authorized users will be able to access information through two web-based interfaces directed to physician and non-physician users respectively. Hospitals are connected through a virtual private network to exchange patient information and users need to obtain a private key from the certificate authority in order to securely connect to MIEC. A pilot project was conducted to demonstrate the feasibility of this architecture and the problems encountered were discussed.

Glutamine utilization in activated lymphocytes from rats receiving endotoxin

BACKGROUND

A beneficial effect of supplemental glutamine for lymphocyte function in patients under metabolic stress has been suggested. Nevertheless, it is not clear how glutamine is used by lymphocytes when under stress. This time course study investigated the effect of endotoxin-induced stress on in vitro glutamine utilization and glutamine-dependent proliferation of activated lymphocytes.

METHODS

Metabolic stress was modeled by intraperitoneal (ip) administration of endotoxin (5 mg/kg body wt) to rats. Control animals were injected with sterile saline. Cervical lymph node lymphocytes collected from animals 6, 12, 24, and 48 h following injection were activated with concanavalin A. Proliferation of these activated lymphocytes in the presence of 0.1-2 mM glutamine was determined. The glutamine utilization rate and glutaminase activity in the activated lymphocytes were also determined.

RESULTS

The proliferation rate of lymphocytes was not affected by ip administration of endotoxin 6 h following the insult, however, 12, 24, and 48 h following the insult, the maximal response was suppressed (P < 0.05). In addition, at 12, 24, and 48 h, the concentration of glutamine for the maximal response of lymphocytes was lower than that for the control group (P < 0.05). Throughout the investigation period, both the glutamine utilization rate and glutaminase activity in the activated lymphocytes were decreased time-dependently.

CONCLUSION

The present study demonstrates that glutamine utilization by lymphocytes under a mitogenic challenge in vitro is significantly decreased in the late period after endotoxin injection. This is at least partly due to decreased glutaminase activity and is associated with decreased proliferation rate of mitogen-activated lymphocytes.

Effects of garlic oil and its organosulfur compounds on the activities of hepatic drug-metabolizing and antioxidant enzymes in rats fed high- and low-fat diets

We examined the effects of garlic oil (GO) and two of its organosulfur compounds, diallyl sulfide (DAS) and diallyl disulfide (DADS), on the drug-metabolizing and antioxidant systems in rats and sought to determine whether these effects are associated with dietary fat. Rats were fed a high-fat diet and received GO or DADS (200 mg/kg body wt) or DAS (100 mg/kg) orally three times a week for seven weeks. Control animals received corn oil alone. Another group of rats was fed a low-fat diet, with or without GO. GO and DADS significantly reduced the body weight gain of rats (p < 0.05). GO, however, dramatically increased the spleen weight and spleen weight-to-body weight ratio (p < 0.05). DAS increased glutathione S-transferase (GST) and 7-pentoxyresorufin O-dealkylase activities, whereas DADS increased only GST activity (p < 0.05). Immunoblot assay showed GO-, DAS-, and DADS-enhanced expression of the placental form of GST and cytochrome P-450 IIBI but suppressed cytochrome P-450 IIEI expression. Hepatic antioxidant enzyme activities were also modulated by these garlic components. GO and DADS inhibited glutathione peroxidase activity (p < 0.05), and DADS and DAS enhanced glutathione reductase activity (p < 0.05). Only GO enhanced the superoxide dismutase activity (p < 0.05). All these garlic components increased glutathione levels in red blood cells (p < 0.05) but did not influence hepatic glutathione levels. Although the amount of fat in the diet modulated drug-metabolizing and antioxidant functions, no interactions between GO and dietary fat were observed. These results indicate that GO and its allyl sulfide components, as well as dietary lipid, modulate drug-metabolizing and antioxidant enzyme activities. The action of GO appears to be independent of dietary lipid content.

Immunogenicity of an inactivated Rift Valley fever vaccine in humans: a 12-year experience

Rift Valley fever (RVF) virus causes serious and fatal disease in animals and man. To protect personnel who work with RVF virus in the laboratory, or troops who may be exposed to this virus, the US Army successfully developed an improved version of inactivated RVF vaccine, TSI-GSD-200. From early 1986 to late 1997, 598 at-risk workers at the US Army Medical Research Institute of Infectious Diseases (USAMRIID) were vaccinated as part of an occupational safety and health program. The subjects of this study received three subcutaneous doses (0, 7 and 28 days) of 0.5 ml of TSI-GSD-200. A total of 540 vaccinees (90.3%) initially responded (group A) with an 80% plaque-reduction neutralization antibody titer (PRNT80) of > or =1:40; whereas 58 subjects (9.7%) were initial nonresponders (group B) failing to achieve this titer. Volunteers who either failed to respond or who achieved a titer of > or =1:40 but whose titer waned below 1:40 were boosted 1-4 times with the same vaccine. Among 247 group A subjects who received the first recall injection, 242 (98%) were successfully boosted, achieving a PRNT80 > or =1:40. Thirty-three of 44 (75%) initial nonresponders were converted to responder status after the first booster, which is a lower rate than that of group A (P < 0.001). After the primary series and the first booster, Kaplan-Meier analysis showed 50% probability of group A members maintaining a titer of > or =1:40 for approximately eight years; whereas group B had a 50% probability of maintaining a titer for only 204 days. Group A immune response rates to boosts 1-4 ranged from 87 to 100% with geometric mean titers (GMTs) ranging from 80 to 916. Boosts 1-4 immune response rates of group B volunteers ranged from 67 to 79% with GMTs ranging from 90 to 177. Minor side effects to TSI-GSD-200 were noted in 2.7% of all vaccinees after primaries and 3.5% of all vaccinees who had primaries and up to four boosters. We conclude that the use of TSI-GSD-200 is safe and provides good long-term immunity in humans when the primary series and one boost are administered.

A unified multimedia database system to support telemedicine

A unified approach to managing multimedia medical databases in a telemedicine system is proposed. In order to manage, search, and display patient information more efficiently, we define a patient information package (PIP) as a concise data set of a patient's medical information from each visit. By means of PIP's, both patient-oriented and problem-oriented query strategies, which are most frequently used in daily clinical practice and medical education, can be accommodated. We also provide a unified methodology for accessing various types of patient medical records as well as design two types of user interfaces, high-quality data display and web-based interface, for different medical service purposes. The PIP-based management of databases has been successfully implemented between the National Taiwan University (NTUH), Taipei, and the Chinshan health care center, Chinshan, Taiwan, for teleconsultation, telediagnosis, and tele-education.

Formation of basement membrane-like structure terminates the cellular encapsulation of microfilariae in the haemocoel of Anopheles quadrimaculatus

The encapsulation of microfilariae in the haemocoels of mosquitoes combines both humoral and cellular reactions: the microfilariae are first encased in an acellular layer of melanin, followed by a cellular encapsulation by plasmatocytes. In this study, we demonstrated that cellular encapsulation of Brugia pahangi microfilariae in the haemocoel of the mosquito Anopheles quadrimaculatus was terminated by the formation of a basement membrane-like structure on the outermost surface of the cellular capsule. This structure occurred in the early stage of cellular encapsulation and was evident on the exterior surface of the plasmatocyte, when the active haemocytes were attaching to the already melanized microfilariae. The termination structure appears to be laid down by releasing the vesicle inclusions of haemocytes and has similarities in ultrastructure and cationic colloidal gold staining properties with that of mosquito basement membranes.

Integrated medical informatics with small group teaching in medical education

National Taiwan University College of Medicine (NTUCM) introduced small groups of teaching and basic-clinical integrated courses for medical students in 1992. By using computer network and multimedia techniques, this study tried to overcome barriers to learning in small group teaching. The Department of Medical Informatics of NTUCM established campus networking and computer classrooms and provided Internet and intranet network services including mail, netnews, bulletin board systems (BBS), world wide web (WWW), gopher, ftp and local file servers. To implement an interactive learning environment, the authors first tried mail lists, newsgroups and BBS. Next an integrated learning system prototype on the WWW was developed to provide functions including online syllabus, discussion boards simulated to BBS, online talk, interactive case studies, virtual classroom with video on demand (VOD) and Internet medical resources. The results showed that after the medical students completed the required course of medical informatics and had good network access using a network to communicate with each other became a daily practice. In the future, the system will extend to the tutoring of clinical practice and continuing medical education. The authors expect a national medical education network and more international cooperation and exchange.

Molecular cloning, characterization and tissue expression of prophenoloxidase cDNA from the mosquito Armigeres subalbatus inoculated with Dirofilaria immitis microfilariae

A cDNA encoding mosquito Armigeres subalbatus prophenol oxidase (As-pro-PO) was obtained by rapid amplification of cDNA ends-polymerase chain reaction (RACE-PCR) after Dirofilaria immitis inoculation. The 2205 bp As-pro-PO cDNA contains a 32 bp 5'-noncoding region, a 2055 bp open reading frame (685 amino acids), and a 118 bp 3'-noncoding region. Hydrophobic signal peptide for the endoplasmic reticulum targeting is not found in the NH2-terminal region. Two potential copper-binding domains, amino acids 197-245 and 345-412, are highly homologous to those of the other insect pro-POs. A 2.2 kb As-pro-PO transcript was identified by Northern blot analysis using D. immitis microfilariae-inoculated A. subalbatus. Both in situ hybridization and Northern blot analysis demonstrated that As-pro-PO mRNA was synthesized in mosquito haemocytes but not in other tissues, i.e. fat bodies, midguts and ovaries, etc.

Effects of inhibitors of serine protease, phenoloxidase and dopa decarboxylase on the melanization of Dirofilaria immitis microfilariae with Armigeres subalbatus haemolymph in vitro

The melanization of Dirofilaria immitis microfilariae in Armigeres subalbatus haemolymph in vitro is a two-step process. Firstly, the microfilariae are encased in a transparent capsule, then the capsule material is melanized later. Benzamadine HC1 and p-amidinophenylmethanesulfonyl fluoride, both serine protease inhibitors, inhibited the deposition of the transparent capsule material and melanization. Diethyldithiocarbamate, a phenoloxidase inhibitor, did not prevent the deposition of the transparent capsule material but it did inhibit melanization. m-Hydroxybenzylhydrazine, a dopa decarboxylase inhibitor, had no inhibitory action on the deposition of the transparent capsule material. However, the time for the transparent capsule to become melanized was delayed due to the presence of m-hydroxybenzylhydrazine in the test system. Immmunocytochemical localization showed that propheoloxidase and/or phenoloxidase was present in the transparent capsule material. These results suggest (1) that prophenoloxidase cascade is essential in the melanization of microfilariae in mosquitoes and its putative activation behaviour is similar to that of other insects and (2) that the deposition of transparent capsule material is the result of the activation of prophenoloxidase by serine proteases and the melanization of the transparent capsule material is due to the presence of active phenoloxidase in capsule.

Lidocaine-induced CNS toxicity--a case report

Lidocaine is the first local anesthetic of the amide type to be introduced to clinical practice. It is a versatile drug and in anesthesia, is the most commonly used local anesthetic because of its aptness of potency, rapid onset, moderate duration of action and topical activity. It is relatively safe and useful in many other clinical settings. Unfortunately, systemic intoxication and psychotic reaction associated with its use often occur because of its popularity and wider safety margin, for which guide in use is often ignored and overdose becomes commonplace. Moreover, due to its universality in use seldom reports have recently dealt with lidocaine, particularly regarding its toxic reaction. Here, we present a case of lidocaine intoxication occurring during circumcision for a reviewal of the problem. A healthy young male, weighing 65 kg, underwent circumcision for phimosis under penile block with 2% lidocaine which totaled 600 mg. Twenty minutes after injection the patient developed headache, tinnitus, visual and auditory disturbances. Muscle twitching over the mouth angles, trismus and rigidity of extremities were also noted. Later in the course he became restless, agitative, hallucinative, talkative, and verbose with repetitious words. The whole course of the disorder lasted about 5 h. It was believed that lidocaine-induced CNS intoxication, manifested by psychotic reaction broke out. Treatment with thiopental was not very impressive. Also, we took this opportunity to discuss and review the toxic reaction associated with the use of lidocaine, its risk factors, mechanism, treatment and prevention. The complicated associations of lidocaine-induced CNS toxic reaction with central control of behavior and the neurotransmitter systems (adrenergic, dopaminergic and serotonin) were also touched.

Role of atrial natriuretic peptide in disturbed water and electrolyte metabolism of guinea pigs infected with Pichinde virus

Daily intake and output of water and electrolytes (Na+, K+, and Cl-) were determined for 14 days in control and Pichinde virus-infected strain-13 guinea pigs. Although water intake began to decrease 7 days after virus inoculation, total daily water output (insensible water loss, urine excretion, plus fecal water loss) had little change. However, insensible water loss alone increased markedly in the virus-infected animals. Both intake and excretions of urinary and fecal electrolytes decreased at the middle (days 7 to 10) and late (days 11 to 14) stages of viral infection. Differences between intake and output of water and electrolytes were reduced significantly during these periods. To determine a possible relationship between atrial natriuretic peptide (ANP) and urinary Na+ and water excretion over intake, we measured plasma ANP concentrations. The mean control value of plasma ANP was 24 +/- 1.0 pg/ml, and plasma ANP concentrations of infected animals increased significantly (P < 0.01) to 49.5 +/- 3.9 and 51.3 +/- 8.8 pg/ml on postinoculation days 7 and 12. Because the overall physiologic responses to Pichinde virus infection are complicated, it is difficult to postulate a single central theme concerning the pathogenesis. Nevertheless, we hypothesize that the virus-induced invisible tissue "biochemical lesions" and the consequential release of mediators and hormones were possible causes of death. Among other pathophysiologic mechanisms, the increased plasma ANP concentration may have played a role in the development of disturbed water and electrolytes metabolism during Pichinde virus infection.

Cardiovascular and pulmonary responses to Pichinde virus infection in strain 13 guinea pigs

In fatal human Lassa fever, severe hypotension, circulatory shock, and pulmonary edema develop as terminal events. We examined cardiovascular and respiratory functions in strain 13 guinea pigs infected with Pichinde virus, an animal model for studying human Lassa fever. Cardiovascular functions were studied in anesthetized and conscious guinea pigs, whereas pulmonary functions were measured only on animals under anesthesia. In anesthetized animals, cardiovascular disturbances were severe and progressive from postinoculation day (PID) 10. Cardiac output, measured by thermodilution, decreased 28 to 53% below baseline values from PID 10 to 12 and was accompanied by a gradual reduction of mean arterial blood pressure and heart rate. Although left ventricular systolic pressure decreased significantly, the left ventricular +dp/dtmax and -dp/dtmax decreased only slightly on PID 12. Similar depressed cardiovascular responses were observed in conscious animals infected with Pichinde virus. Changes included decreased cardiac output, heart rate, cardiac work, cardiac power, and stroke volume, as well as increased total peripheral resistance and prolonged mean transit time. We postulate that a global cardiovascular dysfunction with the involvement of right and left sides of the heart may be the main cause of irreversible circulatory deterioration and death during Pichinde virus infection in strain 13 guinea pigs.

[Teaching sociology in medical school]

As early as in 1994 medical education was criticised by the Royal College of Physician in London. Nevertheless until 1978 D. C. Maddision was still asking the question: "What's wrong with medical education?", and Abrahamson writing a paper called "Disease of the (medical) curriculum". Since the 1950s social and behavioural sciences have been gradually brought into the curriculum in order to pursue better medical care. In the 1970s critics of medicine went beyond its economical and political aspects, ie. its maldistribution etc., to its cultural side. Not only the efficacy of modern medicine but its moral neutrality and benevolence were called into question. This paper is mainly based on the writer's personal experience of teaching sociology and medical sociology in a medical school in Taiwan. The debate on relevance, the difficulties and problems in teaching and suggestions for the future are covered.

Clinical application of 131I-HIPDM in the patients with chronic obstructive pulmonary disease

N,N,N'-trimethyl-N'-2 hydroxy-3-methyl-5-iodobenzyl-1,3-propanediamine iodine-131 (HIPDM) as a lung imaging and metabolic tracer in patients with chronic obstructive pulmonary disease (COPD) were used. 0.4 mCi 131I-HIPDM was rapidly injected into the antecubital vein. The imaging of 131I-HIPDM in the lung was different in various groups. 131I-HIPDM of the clearance by the lungs was a biphasic curve (rapid phase and slow phase). It was displayed that rapid phase of the clearance curve of 131I-HIPDM in the lungs in subjects with chronic obstructive pulmonary emphysema, especially those of smokers were very slow. The rapid phase of the 131I-HIPDM of the right lung clearance was significantly correlated with Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), Functional Residual Capacity (FRC), Residual Volume (RV), Total Lung Capacity (TLC) p < 0.01; Peak Expiratory Flow Rate (PEFR), Vital Capacity (VC), Maximum Ventilatory Volume (MVV), Arterial oxygen tension (PaO2) p < 0.05. Smoking influence on clearance of 131I-HIPDM of the lung including normal smokers with normal lung function. It was considered that the analysis of the lung release of 131I-HIPDM forms a new lung dysfunction index and it was useful that found early lung damage.

Prolonged lung retention of 131I-HIPDM in smokers

Thirty-five subjects were divided into 4 groups; the first group was composed of 8 healthy nonsmoking subjects; the second group included 8 healthy smokers; the third group included 12 nonsmoking patients suffering from chronic obstructive pulmonary emphysema; the fourth group was composed of 7 smokers with chronic obstructive pulmonary emphysema. N,N,N'-trimethyl-N'2-Hydroxy-3-Methyl-5-iodobenzyl-1,3-propanediamine iodine-131(HIPDM) was rapidly injected into the antecubital vein. The influence of 131I-HIPDM by lung clearance was analysed thought imaging of lung and ratio of prolongation of 131I-HIPDM in the lung. Prolongation of 131I-HIPDM in the lung was shown in the smokers with chronic obstructive pulmonary emphysema in 60 minutes, and the healthy smokers, smokers with chronic obstructive pulmonary emphysema in the 24 hours after the injection of 131I-HIPDM. Smoking is an important factor of disturbance of lung clearance.

Changes in platelet-activating factor, catecholamine, and serotonin concentrations in brain, cerebrospinal fluid, and plasma of pichinde virus-infected guinea pigs

Brain concentrations of platelet-activating factor (PAF), catecholamines, and serotonin were measured in control and Pichinde virus-infected strain 13 guinea pigs on postinoculation day (PID) 12. After virus inoculation, PAF concentrations increased 81% in cerebrum, 147% in diencephalon-brain stem, and 110% in cerebellum from baseline values of 2.6 +/- 0.3, 4.3 +/- 0.2, and 6.1 +/- 0.5 (ng/g wet tissue), respectively. Dopamine concentrations in the infected cerebrum and diencephalon-brain stem increased significantly, whereas norepinephrine concentration increased only in cerebrum. However, serotonin concentrations in all three regions of infected brain decreased significantly as compared with control values. There were no significant changes in epinephrine concentrations of infected brain. Norepinephrine and epinephrine concentrations in plasma and cerebrospinal fluid on PID 7 and 12 increased significantly as compared with control values, while plasma dopamine concentration increased significantly on PID 7. Increased brain PAF, dopamine, and and norepinephrine concentrations with decreased brain serotonin concentrations may mediate the hyperactivity of the hypothalamic-pituitary-adrenal axis and involve some unknown pathophysiologic processes of arenaviral infection. Furthermore, increased plasma catecholamine concentrations are associated with stress and may be partially responsible for the development of cardiovascular dysfunction and pulmonary edema during this viral disease.

Platelet-activating factor (PAF)-induced cardiopulmonary dysfunctions and their reversal with a PAF antagonist (BN 52021) in strain 13 guinea pigs

Cardiovascular and respiratory responses to a 2 h intravenous constant infusion of PAF (5 and 10 ng/kg per min) were studied in strain 13 guinea pigs. PAF decreased arterial blood pressure, left systolic ventricular pressure, and cardiac output (CO). These cardiovascular changes were dose-dependent. The PAF-induced hypotension returned to a pre-infusion level spontaneously with increased total peripheral resistance despite continuous infusion of PAF. The decreased CO was most striking, and did not recover to pre-infusion levels due to depressed cardiac contractility and impaired ventricular relaxation. Respiratory responses to PAF infusion at these doses were mild and only occurred after serious cardiovascular dysfunctions developed. A higher dose of PAF (20 ng/kg per min) produced drastically decreased CO and dynamic lung compliance (Cdyn), increased pulmonary airway resistance, hypoventilation and apnea within 10-40 min. BN 52021, a PAF receptor antagonist, administered as a single i.v. dose (6 mg/kg) 15 min after PAF infusion, reversed most of cardiopulmonary dysfunctions and prevented death by increasing cardiac contractility, CO, and minute volume from extremely low values. The data suggest that marked cardiopulmonary disturbances induced by intravenous PAF infusion reflects certain pathophysiological mechanisms of diseases that may involve the cellular release of PAF. The administration of BN 52021 or other potent PAF antagonists may be beneficial under these circumstances.

The effects of growth hormone and insulin-like growth factors I and II on glutamine metabolism by skeletal muscle of the rat in vitro

Soleus muscle preparations of the rat were incubated in the presence of growth hormone, IGF-I or IGF-II. Growth hormone (10 and 100 ng/ml) increased, but IGF-I and IGF-II were without effect on the concentration of glutamine in soleus muscle. Growth hormone was without effect on the rate of release of glutamine from muscle. In contrast, the rate of release of glutamine was decreased in the presence of IGF-I (750 ng/ml) and increased in the presence of IGF-II (250 and 750 ng/ml). Growth hormone and the IGFs may therefore play an important role in the control of glutamine metabolism by skeletal muscle.

Acute ethanol administration and the metabolism of glutamine by skeletal muscle of the rat: implications for ethanol-induced reductions in protein synthesis

The effect of acute ethanol administration (75 mmol/kg) on the metabolism of glutamine by skeletal muscle of the rat was studied in order to investigate the hypothesis that the concentration of this amino acid in muscle controls the rate of protein synthesis. Ethanol administration was without effect on the concentration of glutamine in EDL (extensor digitorum longus) and plantaris muscles (Type II fibre-rich muscles), but increased the concentration in soleus muscle (Type I fibre-rich muscle). The rate of release of glutamine was increased from EDL muscle, but unchanged from soleus muscle of treated animals. Ethanol administration was without effect on the maximal activity of glutamine synthetase in both soleus and EDL muscles. It is concluded that changes in the concentration of glutamine in muscle cannot explain the ethanol-induced changes in the rate of protein synthesis. Nevertheless, the increase in the concentration of glutamine in soleus muscle following ethanol administration is of interest and may be mediated via modulation of the glutamine transporter and/or the activity of glutamine synthetase in vivo.

[Clinical evaluation of the metabolism and imaging of the lung in the patients with chronic obstructive pulmonary diseases using 131I-HIPDM]

The accumulation of venously injected 131I-HIPDM in the rat lung was observed. In this article we report the results of application of 131I-HIPDM in the patients with COPD. The results showed that the metabolism and development of 131I-HIPDM in the lung reflected on condition of the pulmonary endothelial cells or receptors. The clearance curve of HIPDM displayed that COPD, especially COPD of smokers was slow. The analysis of the lung clearance of 131I-HIPDM forms a new index of lung dysfunction.

The effect of insulin-like growth factor II on glucose uptake and metabolism in rat skeletal muscle in vitro

The effect of insulin-like growth factor II (IGF II) on the rates of lactate formation, glycogen synthesis and glucose transport in the presence of a range of concentrations of insulin were investigated using an isolated preparation of rat skeletal muscle. IGF II, at a concentration of 65 ng/ml, caused a small but significant increase in the rates of these processes at a basal physiological insulin concentration (10 muunits/ml), but was without effect in the presence of 1, 100, 1000 or 10,000 muunits of insulin/ml. Hence IGF II increased the insulin sensitivity of this tissue. This effect was removed if the incubation medium was supplemented with an equimolar concentration of IGF binding protein 1 (BP1). It is suggested that changes in the concentration of IGF II and/or BP1 may regulate glucose uptake and metabolism in skeletal muscle and have physiological significance in the control of blood glucose level.

Increased platelet-activating factor (PAF) concentrations in hearts and lungs of Pichinde virus-infected guinea pigs

Platelet-activating factor (PAF) has been implicated as a cause of cardiopulmonary disturbances in certain diseases. In the present study, concentrations of PAF in hearts, lungs, whole blood, and other organs of control and Pichinde virus-infected guinea pigs on post-inoculation days (PID) 10 and 14 were measured by radioimmunoassay. Results were further confirmed by bioassay after separation and purification with thin-layer chromatography. PAF concentration in the hearts and lungs of virus-infected animals increased significantly on PID 10 and 14, as compared with control levels. PAF level in the blood of infected guinea pigs also significantly increased on PID 14. There was little change of PAF levels in liver and kidney after viral inoculation. Increased PAF concentrations in both hearts and lungs of infected strain 13 guinea pigs suggest that this lipid mediator may play an important role in the development of cardiopulmonary disturbances.

Possible involvement of endogenous beta-endorphin in the pathophysiological mechanisms of Pichinde virus-infected guinea pigs

Previously, we demonstrated that naloxone, an opiate antagonist, prolonged survival of strain 13 guinea pigs infected with Pichinde virus. Thus, endogenous opiates may be involved in the pathogenesis of this viral disease. To determine whether endogenous opiate levels were affected by Pichinde viral infection, beta-endorphin concentrations in plasma and cerebrospinal fluid (CSF) of normal and infected strain 13 guinea pigs were measured by radioimmunoassay. Cerebrospinal fluid beta-endorphin concentrations were 78.0 +/- 13.2 pg/ml on postinoculation day (PID) 7, 59.0 +/- 5.6 pg/ml on PID 12, and 58.8 +/- 5.4 pg/ml on PID 14. These values were significantly higher than baseline levels of CSF beta-endorphin: 30.8 +/- 1.9 pg/ml. Plasma beta-endorphin concentrations of infected animals increased significantly to 202.1 +/- 17.9 pg/ml on PID 7 and to 154.2 +/- 21.4 pg/ml on PID 12 from a mean baseline value of 84.2 +/- 13.1 pg/ml. After a primer intravenous injection of beta-endorphin (10, 15, or 30 micrograms/kg), followed by constant infusion of beta-endorphin (15, 45, or 90 micrograms/kg.hr) to control noninfected guinea pigs, heart rate (except with the lowest dose) and mean blood pressure decreased markedly. Under these experimental conditions, concentrations of plasma and CSF beta-endorphin increased simultaneously with different magnitude. Because both Pichinde viral infection and beta-endorphin administration produced a similar trend of cardiovascular disturbances, leading to hypotension and bradycardia, increased concentrations of plasma and CSF beta-endorphin may play a partial role in the pathophysiological mechanisms of Pichinde virus infection.

Cardiovascular responses to intracerebroventricular infusion of artificial cerebrospinal fluid in anesthetized strain 13 guinea pigs

The cardiovascular effects of constant intracerebroventricular infusion in anesthetized strain 13 guinea pigs were studied. Bilateral cerebroventricles of the animals were catheterized stereotaxically with two 20-gauge blunt needles, penetrating 5 to 6 mm into the skull. Baseline cerebroventricular pressure values were 1.3 +/- 0.6 mmHg. After artificial cerebrospinal fluid was infused into the left ventricle at 0.5 ml/h, left cerebroventricular pressure increased to 8.1 +/- 1.6 mmHg (P less than 0.01), while right cerebroventricular pressure reached 5.6 +/- 2.2 mmHg within 20 minutes. No significant changes in mean blood pressure or heart rate were observed. When intracerebroventricular infusion rate increased to 5.0 ml/h, cerebrospinal fluid pressures of left and right cerebroventricles increased to 40.0 +/- 4.8 and 38.4 +/- 4.7 mmHg within 10 minutes from baseline values of 1.5 +/- 0.5 and 1.7 +/- 0.7 mmHg, respectively. Simultaneously, mean blood pressure and heart rate increased from 72 +/- 4 to 101 +/- 9 mmHg and from 195 +/- 11 to 218 +/- 17 beats/min, respectively. However, 30 to 50 minutes later, mean blood pressure, heart rate, and cerebrospinal fluid pressure decreased abruptly, and two of four animals died. We suggest that this technique with a low infusion rate (less than 0.5 ml/h) can be used to deliver certain drugs into the brain ventricles directly without producing undesirable effects on blood pressure or heart rate.

[Lung function changes during pregnancy]

The lung functions in different pregnant stages were measured in 41 women with pregnancy and 12 normal women without pregnant. Forced Vital Capacity (FVC) was found gradually decreasing as pregnancy advanced (P less than 0.05). After 28 weeks of gestation, the Vital Capacity (VC), Forced Expired Volume in 1 second (FEV 1) significantly decreased as compared with the normal values (P less than 0.01 or P less than 0.05). These results suggested that the lung function changed gradually during pregnancy, especially after the 28th week, significantly in VC, FVC and FEV 1. Maybe there are slight obstructions in the bronchial tubes. After the 28th week of gestation and it may be the reason for occurrence of breathshort and the lung infection.

Metabolism of platelet-activating factor in neutrophils isolated from Pichinde virus-infected guinea pigs

Metabolism of platelet-activating factor (PAF) was studied in cultured polymorphonuclear neutrophils (PMNs) obtained from Pichinde virus-infected strain 13 guinea pigs. Neutrophils obtained from control and infected guinea pigs on postinoculation days 10 and 14 were incubated with [3H]lyso-PAF, [3H]PAF, or [3H]acetate. After incubation for 1 h at 37 degrees C, formation of [3H]acyl-PAF from either [3H]lyso-PAF or [3H]PAF increased significantly in PMNs from infected guinea pigs compared to control PMNs. Furthermore, total radioactivity from [3H]lyso-PAF or [3H]PAF was higher in PMNs from infected animals than in those from controls. However, compared to PAF production by control PMNs, production of PAF by infected PMNs was unchanged. These results suggest that PMNs may not be the major source of increased blood PAF levels during Pichinde viral disease.

Technique for repeated collection of cerebrospinal fluid from cisterna magna of anesthetized strain 13 guinea pigs

To study biochemical changes in cerebrospinal fluid (CSF), we developed a reliable technique for repeated collection of CSF in anesthetized strain 13 guinea pigs. The animal's head was mounted in a stereotaxic instrument with ventral tilt at 30 degrees, and cisternal puncture was made with an L-shaped, 23-gauge needle through the shaved skin. Clear CSF was collected in a 1-ml syringe surrounded by crushed ice. Each collection procedure lasted for 3 min, and three consecutive collections produced about 0.2 ml of CSF. Sampling was repeated at 3-hr intervals. With intravenous saline infusion (10 ml/kg.hr), a total volume of 0.6-1.0 ml of CSF was collected over 6 to 12 hr. Animals maintained a mean blood pressure, heart rate, and minute volume, with few changes during CSF sampling for the entire collection.

Pulmonary function in patients with pleural effusion of varying magnitude and fibrothorax

Pulmonary function was studied in sixty patients with pleural effusion and seventy patients with fibrothorax. The patients with pleural effusion were divided into three groups according to the extent of the effusion. The patients were submitted to spirometry and arterial blood gas analysis. The effects of pleural effusion on pulmonary function is evaluated with regards to the size of effusion. Small-size pleural effusion little affects arterial oxygen tension. Pleural effusion and fibrothorax have a similar pattern of pulmonary function.

Room-temperature microparticle-based persistent spectral hole burning memory

We show both theoretically and experimentally that a random distribution of spherical microparticles may be used as a spectral hole burning memory. This microparticle hole burning memory, which can be both written and read at room temperature, is a direct consequence of the properties of morphology-dependent resonances of microparticles.

From san gu liu po to 'caring scholar': the Chinese nurse in perspective

This study presents a re-evaluation of the origins of Chinese nursing from the earliest traditional carers to the mature, professionalized institution of the republican period. The influence of traditional cultural values on the nature of the modern profession is discussed and its emergence considered in historical context with particular attention to the role of missionaries, philanthropic institutions and other aspects of foreign intervention, both European and Japanese. The Chinese anti-imperialist response, as stimulated by the 'May 4th Movement' and later the Sino-Japanese war, is shown to be an important ingredient in the transition from foreign to national control of the profession and in its achieving respect. Some doubt is cast on the assumption that Chinese nursing has followed a process of rapid convergence to the Western model.

Pulmonary function in the patients submitted to lung exeresis

The effects of lung surgery on respiratory function were investigated in 80 patients; 17 patients were submitted to left pneumonectomy (LPN); 11 patients were submitted to right pneumonectomy (RPN); 7 patients underwent a left upper lobectomy (LUL); 16 patients a left lower lobectomy (LLL); 17 patients were submitted to right upper lobectomy (RUL); 12 patients underwent right lower lobectomy (RLL). All patients were submitted to spirometry and arterial blood gas analysis. The effects of lung surgery on respiratory function depends upon the extent of the resected tissue.

[A preliminary study on the role of interleukin-1 in chronic lung disease]

Pulmonary alveolar macrophages (PAM) obtained by bronchoalveolar lavage in 13 normal individuals, 17 lung cancer patients and 10 patients with chronic obstructive pulmonary disease (COPD) were incubated in vitro for 24 hours. Every specimen was divided into two portions and lipopolysaccharides were used to stimulate PAMs to produce interleukin-1 (1L-1) in one. The levels of 1L-1 in normal subjects were 5547.65 +/- 2420.42 cpm/10(6) cells (stimulated) and 718.46 +/- 472.25 (unstimulated), which were higher than the 2733.20 +/- 1611.17 (stimulated, P less than 0.01) and 327.57 +/- 226.86 (unstimulated, P less than 0.05) in lung cancer patients, but lower than that of 8716.26 +/- 2977.66 (stimulated, P less than 0.05) in COPD patients. The enhanced 1L-1 activity in COPD patients might contributed to the active inflammatory process and tissue destruction of COPD. Our findings that 1L-1 activity in patients with bronchogenic carcinoma was decreased may reflect the local immune deficiency in malignant disease. The release of 1L-1 by PAMs stimulated by smoking was suggested to be associated with the development of COPD, but its role in immune response has to be determined.

[A survey on weight and height of children (1 month-7 years) and plotting of growth curves (1 month-18 years) in Taiwan, 1987-1988]

From July 1987 to December 1988, 19,625 children in Taiwan were measured for their body weights and heights. They were 9,564 boys and 10,061 girls and were seen either in a well baby clinic of a large community hospital or in the local kindergartens. We divided these children into 64 groups according to their sex and ages. The mean values and standard deviation of body weight and height were tried to correlate with those from children of school age reported for 1987 by the Ministry of Education. Furthermore, body weight and height growth curves were drawn for these children, aged from 1 month to 18 years.

Effect of ethanol on natural killer cell activity in vitro

The effect of ethanol on kinetic stages of natural killer (NK) cell activity was studied in vitro. Peripheral blood mononuclear cells (MNC) were either co-cultured or pre-incubated with various ethanol concentrations and assayed for NK cell activity with a "4-hour chromium release assay" and a "single cell cytotoxicity assay in agarose" simultaneously. Direct addition of ethanol to the assay system resulted in a dose-dependent inhibition of NK cell activity. The percentage of lysed conjugated target cells was suppressed from a control value of 21.2% to 17.0%, 15.1%, 11.8% and 10.0% with an ethanol concentration of 0.125%, 0.25%, 0.5% and 1.0%, respectively. NK cell recycling was also inhibited. A 24-hour pre-incubation with ethanol, however, resulted in NK cell activity enhancement. The enhancement was around 20% with a 0.25% ethanol concentration and around 45% with a 0.5% and a 1.0% ethanol concentrations. The enhancing effect was noted mainly at the cytolysis stage after binding of effector cell with target cells.

Pathogenesis of viral hemorrhagic fevers: Rift Valley fever and Lassa fever contrasted

Although many viral infections have on occasion been associated with hemorrhagic complications, infection with any of several RNA viruses regularly results in vascular involvement and the syndrome called viral hemorrhagic fever (VHF). In spite of clinically useful similarities among various VHFs, there are significant differences in their pathogenesis and clinical evolution; these are often related to characteristics of their viral taxon. Infection with Rift Valley fever (RVF) virus, a phlebovirus, appears to be regulated by interferon and terminated by neutralizing antibody. In contrast, Lassa fever (LF) virus, an arenavirus, is resistant to interferon, and LF is terminated by cellular immune effector mechanisms. The lytic virus-cell interaction typical of RVF virus suggests its major effects occur by direct, virus-induced cellular necrosis, particularly in the liver. In the primate RVF model, disseminated intravascular coagulation (DIC) may be important. LF virus--characteristically noncytopathic--may exert its effects through induction of mediator secretion from infected macrophages. DIC does not appear to be a central pathogenetic mechanism in LF. Pichinde virus, which is not pathogenic for humans, provides an alternate model for study of LF. Infected guinea pigs do not show histologic lesions that could explain their body wasting, cardiovascular deterioration, and pulmonary edema. In the heart, for example, loss of tissue mass, protein, and contractile function proceed without direct viral involvement or myocarditis. Sulfidopeptide leukotrienes have been implicated as one relevant soluble mediator participating in the disease state.

Changes in body weight and body surface area in strain 13 guinea pigs infected with Pichinde virus

In studying pathogenetic mechanisms of Pichinde virus-induced disease in strain 13 guinea pigs, a large decrease of body weight (approximately 28%) observed within 14 days postinoculation raises a question concerning the validity of standardizing body or organ functions in terms of body weight. This study was to examine changes in body weight and body surface area of Pichinde virus-infected strain 13 guinea pigs after various days postinoculation. Control guinea pigs were also subjected to the same experimental procedures and experimental days. While body weights and body surface areas increased progressively in controls, I observed only slight decreases in body surface areas (4-6%) in the infected guinea pigs, despite large decreases of body weights throughout the 14-day experimental period. In conclusion, Pichinde virus-infected strain 13 guinea pigs demonstrated a small reduction of body surface area within 14 days postinoculation, suggesting that body surface area, rather than body weight, should be used for standardizing body or organ functions for comparison with their own baseline values.

Body surface areas and K values in strain 13 guinea pigs with different body weights and ages

Body surface areas (BSA) were determined for strain 13 guinea pigs with body weights ranging from 191 to 1011 g. For this determination, the entire skin of each animal was removed immediately after death and flattened on a wax film with a homogeneous paper. The skin outlines on the paper were cut and weighed for determining BSA. The K value was calculated for each guinea pig as the ratio of BSA (cm2)/body weight (g)2/3. Significantly different K values of 11.31 +/- 0.11, 9.66 +/- 0.09, 9.22 +/- 0.05, and 9.17 +/- 0.05 were determined for average body weights of 218 +/- 24, 527 +/- 33, 706 +/- 60, and 943 +/- 30 g, respectively. By plotting these K values on semilog paper and determining the best fit curve of the slope, it was possible to extrapolate exponentially the K values for different body weights. The relationship between age and body weight was also established for guinea pigs, and a series of K values were determined from birth to 35 weeks of life. We conclude that a different K value should be used for calculating BSA for various ages and body weights of strain 13 guinea pigs.

Transforming genes in duck hepatic carcinoma--mht(raf) and Ha-ras

The transfection of NIH 3T3 cells was performed with DNAs from 2 duck primary hepatic carcinomas (DHC 40K, 9K) and 1 tumor-adjacent liver tissue (TAL, 9N). Transfectants were found from 40K, 9K and 9N DNAs. The secondary transfectants were obtained after transfection of RAT-1 cells with DNAs from primary transfectants. After hybridization with Ha-ras, Ki-ras, N-ras and mht oncogenes, it was found that duck mht (5.2 and 3.2 kb EcoRI fragments) and duck Ha-ras (3.4 kb EcoRI fragments) were present in all these transformants. This is the first report on transforming genes in duck primary hepatic cancer as well as tumor-adjacent liver tissue.

Energy balance and growth rate of outbred and inbred male guinea pigs

Water intake, food consumption, growth rate, and rectal temperature were measured daily for 14 days and oxygen uptake was determined weekly for 3 weeks in healthy outbred (Hartley stock) and inbred (strains 2 and 13) male guinea pigs. Body weights ranged from 300 to 465 g, and ages were approximately 6 to 10 weeks. Strain-13 guinea pigs had the lowest daily body weight gain (3.27 +/- 0.33 g), when compared with strain-2 (4.04 +/- 1.21 g) and Hartley guinea pigs (5.72 +/- 1.08 g). Outbred guinea pigs also had highest values of water intake and water/food intake ratio(s), and had significantly (P less than 0.05 and 0.01) lower oxygen uptake values than did inbred guinea pigs. The ratio of daily average body weight gain to the corresponding daily retained calories, with or without corrections of body surface area (0.05 m2), was higher in Hartley stock than in the strain-13 guinea pigs. Rectal temperatures and food consumption were similar in all guinea pigs. Data indicated that the outbred Hartley guinea pig had a faster growth rate and appeared stronger physiologically, compared with inbred strains.