Smoking attributable medical expenditures, years of potential life lost, and the cost of premature death in Taiwan

OBJECTIVE

To estimate the smoking attributable medical expenditures and productivity loss of people aged 35 and over in Taiwan in 2001 from a societal viewpoint.

METHODS

A prevalence based approach was used to estimate smoking attributable costs. Epidemiological parameters were obtained from two follow up studies and government statistics. Data on medical care utilisation and expenditure were extracted from the National Health Insurance claim data.

RESULTS

Total smoking attributable medical expenditures (SAEs) amounted to USD 397.6 million, which accounted for 6.8% of the total medical expenditures for people aged 35 and over. Mean annual medical expenditures per smoker was USD 70 more than that of each non-smoker. Smoking attributable years of potential life lost (YPLL) totalled to 217,761 years for males and 15,462 years for females, and the corresponding productivity loss was USD 1371 million for males and USD 18.7 million for females.

CONCLUSION

Medical expenditures attributable to smoking accounted for 6.8% of the total medical expenditure of people aged 35 and over for the year 2001 in Taiwan. Corresponding YPLL and productivity loss also demand that actions be taken to fight cigarette smoking.

Reconstruction of burn scar of the upper extremities with artificial skin

The management of upper-extremity burn contractures is a major challenge for plastic surgeons. After approval by the Food and Drug Administration, artificial skin (Integra) has been available in Taiwan since 1997. From January of 1997 to July of 1999, the authors applied artificial skin to 13 severely burned patients for the reconstruction of their upper extremities, resulting in an increased range of motion in the upper-extremity joints and improved skin quality. An additional benefit was the rapid reepithelialization of the donor sites. There were no complications of infection throughout the therapeutic course, and the overall results were satisfactory. During the 2-year study, scar condition was monitored between 8 and 24 months, and a good appearance and pliable skin were obtained according to the Vancouver Scar Scale. According to this evaluation of Oriental skin turgor, normal pigmentation was restored about 6 months after the resurfacing procedure. For patients with severe burns in whom there is insufficient available skin for a full-thickness skin graft or another appropriate flap for scar revision, Integra is an alternative. The two major concerns in dealing with artificial skin are (1) a 10- to 14-day waiting period for maturation of the neo-dermis, necessitating a two-stage operation, and (2) prevention of infection with antibiotics and meticulous wound care.

CD1b-mediated T cell recognition of a glycolipid antigen generated from mycobacterial lipid and host carbohydrate during infection

T cells recognize microbial glycolipids presented by CD1 proteins, but there is no information regarding the generation of natural glycolipid antigens within infected tissues. Therefore, we determined the molecular basis of CD1b-restricted T cell recognition of mycobacterial glycosylated mycolates, including those produced during tissue infection in vivo. Transfection of the T cell receptor (TCR) alpha and beta chains from a glucose monomycolate (GMM)-specific T cell line reconstituted GMM recognition in TCR-deficient T lymphoblastoma cells. This TCR-mediated response was highly specific for natural mycobacterial glucose-6-O-(2R, 3R) monomycolate, including the precise structure of the glucose moiety, the stereochemistry of the mycolate lipid, and the linkage between the carbohydrate and the lipid. Mycobacterial production of antigenic GMM absolutely required a nonmycobacterial source of glucose that could be supplied by adding glucose to media at concentrations found in mammalian tissues or by infecting tissue in vivo. These results indicate that mycobacteria synthesized antigenic GMM by coupling mycobacterial mycolates to host-derived glucose. Specific T cell recognition of an epitope formed by interaction of host and pathogen biosynthetic pathways provides a mechanism for immune response to those pathogenic mycobacteria that have productively infected tissues, as distinguished from ubiquitous, but innocuous, environmental mycobacteria.

The boomerang flap in managing injuries of the dorsum of the distal phalanx

Finding an appropriate soft-tissue grafting material to close a wound located over the dorsum of a finger, especially the distal phalanx, can be a difficult task. The boomerang flap mobilized from the dorsum of the proximal phalanx of an adjacent digit can be useful when applied as an island pedicle skin flap. The vascular supply to the skin flap is derived from the retrograde perfusion of the dorsal digital artery. Mobilization and lengthening of the vascular pedicle are achieved by dividing the distal end of the dorsal metacarpal artery at the bifurcation and incorporating two adjacent dorsal digital arteries into one. The boomerang flap was used in seven individuals with injuries involving the dorsal aspect of the distal phalanx over the past year. Skin defects in all patients were combined with bone,joint, or tendon exposure. The authors found that the flap was reliable and technically simple to design and execute. This one-step procedure preserves the proper palmar digital artery to the fingertip and has proven valuable for the coverage of wide and distal defects because it has the advantages of an extended skin paddle and a lengthened vascular pedicle. When conventional local flaps are inadequate, the boomerang flap should be considered for its reliability and low associated morbidity.

The effects of pretreatment with glycyrrhizin and glycyrrhetinic acid on the retrorsine-induced hepatotoxicity in rats

A wide variety of medicinal herbs contain hepatotoxic pyrrolizidine alkaloids (PAs), and often cause acute and chronic liver damages in man. Liquorice, a known antihepatitis, is commonly used with PA-containing herbs concurrently, and hepatotoxicity induced by such combined uses was not pronounced. The present study is to investigate effects of glycyrrhizin (GL) and 18beta-glycyrrhetinic acid (GA), the major biologically active ingredients of liquorice, against PA-induced hepatotoxicity in rats. Single dose (35 mg/kg, i.p.) of retrorsine (RET), a typical potent hepatotoxic PA, was given to rats to induce liver injury. A single dose pretreatment with GL or GA prior to retrorsine challenge did not show hepatoprotection. However, when rats were pretreated with either GL (200 mg/kg/day, i.p.) or GA (10 mg/kg/day, i.p.) for three consecutive days prior to retrorsine exposure, the elevated serum GOT and GPT levels induced by retrorsine were significantly reduced. Serum levels of transaminases almost returned to normal (GOT: 56+/-2 (control), 104+/-5 (RET), 64+/-3 (GL + RET) and 59+/-3 (GA + RET). GPT: 40+/-2 (control), 90+/-7 (RET), 45+/-2 (GL + RET) and 45+/-4 (GA + RET) SF units/ml). Furthermore, no extensive hepatocellular damages were observed. The results demonstrated that a three-day pretreatment with either GL or GA exhibited protective effect on retrorsine-induced liver damage in rats.

The comparison of early fluid therapy in extensive flame burns between inhalation and noninhalation injuries

Over the last half century, advances in treatment have changed the principal cause of death in burn patients from burn shock and wound sepsis to pulmonary sepsis, of which inhalation injury has always played a key role in morbidity and mortality. Even though Navar et al., Am. J. Surg. 1985;150:716-720 have noted that patients with inhalation injury had a mean fluid requirement of 5.8 ml/kg/% burn to achieve resuscitation from early burn shock, while patients without inhalation injury required only a mean fluid of 4.0 ml/kg/% burn, to achieve successful resuscitation in inhalation injured patients with minimum but adequate fluid has always been a challenge. To further define the difference of early fluid therapy between inhalation and noninhalation in extensively burned patients, a retrospective analysis was carried out in the Tri-Service General Hospital. Sixty-two flame burned patients (aged from 16 to 81 years-old with a mean age of 33.2+/-15.1 years: with burn size ranging from 30% to 98% TBSA with a mean burn size of 60.5+/-22.7%; 26 with inhalation injury; noninhalation 36) were reviewed during a 5-year period. The Parkland formula is the initial choice of fluid regimen with 4 ml/kg/% burn and the amount of replacement is monitored by urine output and is titrated to maintain urine output between 0.5 and 1.0 ml/kg/h. The mean amounts of fluid requirements of both inhalation and noninhalation burned patients were 3.1 +/- 1.0 and 2.3+/-0.8 ml/kg/% burn respectively (p < 0.05). Our study showed less fluid requirement for both inhalation and noninhalation injured patients in comparison with the Navar study and Parkland predictions in the first 24 h postburn. Furthermore, the inhalation injured patients definitely required volumes of fluid in excess of those required in noninhalation injured cases.

Induction of tumor-specific T cell response by cognating tumor cells with foreign antigen-primed Th cells

Sufficient CD4+ T cell help is very important in generating specific cytotoxic T cell responses. The inadequate activation of tumor-specific Th cells leads to failure of antitumor immunity. In general, each individual consists of some primed Th cells responding to certain antigens. If these tumor non-specific pre-primed Th cells can provide sufficient help, the generation of tumor-specific T cells may be enhanced. In the present study, we tested this hypothesis by cognating and reactivating pre-primed ovalbumin (OVA)-specific Th cells with OVA-pulsed tumor cells which could simultaneously present both OVA and tumor-associated antigen on the same cell. We clearly demonstrated that immunization of OVA-sensitized mice with OVA-pulsed P388 cells, but not unpulsed P388 cells, led to the induction of P388-specific cytotoxicity and tumor resistance. Both CD4+ and CD8+ tumor-specific cytotoxic T cells were detected in vitro, but only CD8+ T cells played the major effector role in preventing the growth of challenged tumor in vivo. Taken together, our study demonstrated that the immunogenicity of tumor cells can be enhanced effectively by cognating pre-primed foreign antigen-specific Th cells with tumor cells. These findings have potential implications in developing methods to control tumor growth.

Skin injury in the operating room

Skin injury occurring in the operating room may occur as a result of electrical current, thermal injury, chemical irritation and mechanical stress. Between 1 December 1996 and 28 February 1997, 19 cases of skin injury from a total of 3657 operations were noted in our hospital. These injuries tend to be ignored because of their early spontaneous healing. We suggest that medical staff should pay more attention to this complication and prevent it from occurring.

Recipient bed vascularity and the survival of ischaemic flaps

The purpose of this study was to identify the length of the ischaemic period required to induce the 'no-reflow' phenomenon in a rat epigastric flap on an avascular recipient site. The vascularity of the recipient bed may affect flap survival in the early postischaemic stage after flap transfer. Initially, we designed epigastric flaps in 300-350 g Sprague-Dawley rats and separated the rats into four groups of 5 rats each (total 20 rats). In groups 1, 2, 3, the flaps were made ischaemic for 1 hour, 6 hours and 10 hours, respectively, by temporarily clipping the epigastric artery and vein. In group 4, the epigastric artery and vein were divided to create permanent ischaemia. In groups 1, 2 and 3, ischaemia was ended by removing the clips. After the ischaemic flaps were reperfused, their viability was studied by measuring the flap survival rate at postoperative day 7. Flap survival was studied by direct observations, laser Doppler flowmeter measurement of flap blood flow, histopathology, and carbon particle perfusion of the flap vasculature. Ischaemic flaps of groups 1 and 2 recovered almost completely after reperfusion due to the short period of ischaema. In a second series of experiments, in order to evaluate the contribution to flap survival of the recipient vascularised bed, another four groups of epigastric flaps (of 5 animals each, using the same time periods as above) were raised and a piece of Biobrane was interposed between the flap and the recipient bed before the flap wound was closed, to eliminate all nutrient supply from the recipient bed. THe results showed that the combined effect of the reperfused flap vasculature plus the metabolic contribution of the recipient bed significantly (P < 0.01) increased the extent of flap survival of the 6- and 10-hour ischaemic flaps as well as the divided pedicle flaps, which were never reperfused. An absolute 'no-reflow' rat model flap for further flap salvage studies was also developed.

Management of pancreatic lesions in von Hippel-Lindau disease

Twelve patients with von Hippel-Lindau disease were collected in our institute from 1981 to 1995. All had a family history of the disease. Eleven patients underwent abdominal computed tomography, sonography, or angiographic studies. Ten had pancreatic involvement that included cystic lesions in nine and a solid lesion in one. Seven patients were asymptomatic. Another three presented with obstructive jaundice or upper gastrointestinal (UGI) bleeding. Except for case 8, who died of a central nervous system complication soon after diagnosis of the pancreatic lesion, the other patients had been found to have pancreatic involvement for a variable period of time, ranging from 1 to 13 years (median 5 years). Serous cystadenoma was proved pathologically in two with cystic lesions, and pancreatic endocrine tumor was diagnosed in one with a solid mass. One patient (case 1) underwent biliary bypass due to obstructive jaundice and died of cholangitis and pneumonia 6 years later. One patient (case 3) had total pancreatectomy and lived well with good diabetic control for more than 5 years. The patient with a solid lesion was explored because of repeated UGI bleeding. Surgical resection was impossible owing to advanced tumor with vascular involvement, and a pancreatic endocrine tumor was diagnosed pathologically. He was followed for 1 year. The other seven patients remained asymptomatic during the successive follow-up period. From a literature review and our own experience, we suggest that conservative measures are adequate for the cystic lesions; however, aggressive resection is mandatory for a solid pancreatic lesion in von Hippel-Lindau disease.

Use of a porcine dermis template to enhance widely expanded mesh autologous split-thickness skin graft growth: preliminary report

To answer the question whether a xenograft dermal substitute could enhance skin grafting, we used porcine dermis as a template for a widely expanded mesh autologous split-thickness skin (ASTS) graft in a rat model. Four groups of rats had received widely expanded meshed skin autografts to cover an excised back wound. Group 1 had a bed of autologous dermis, group 2 had porcine xenograft dermis, group 3 had widely expanded meshed autograft alone, and group 4 had no graft with the wound healing by contraction alone. Wounds were studied by clinical inspection for texture and contraction, and by histologic and immunofluorescent techniques. At 2 weeks, there was acceptable ASTS graft take, and most of the wound healed completely by 3 weeks. The integrity of this complex skin graft was maintained for 4 months but wound contraction gradually decreased overall wound size. Size was maintained better in the ASTS-autodermis and ASTS-xenodermis groups at postgraft 4, 5, and 6 weeks when compared with the ASTS graft, and there was no difference between the ASTS-autodermis and ASTS-xenodermis groups. Thus both allodermis and xenodermis provided a similar template to enhance widely expanded mesh skin growth and delay wound contraction. The pathologic studies indicate that the xenodermis collagen was replaced either by fibrosis or by biodegradation to rat collagen. The immunofluorescent study also reflected that anti-porcine antibody activity was hugely diminished in the ASTS-xenodermis graft wound after long-term follow-up. In conclusion, either autodermis or xenodermis enhances widely expanded mesh ASTS survival in a rat model, and could significantly maintain the original wound size better than ASTS graft without a template. In a long-term follow-up study, the porcine dermis was replaced either by fibrosis or biodegradation to rat dermis.

Prederivatization and high-performance liquid chromatographic analysis of alkaloids of bulbs of Fritillaria

A method of prederivatization and HPLC with UV detection was developed for the simultaneous analysis of five major steroidal alkaloids of the Fritillaria species: verticine, verticinone, isoverticine, ebeiedine, and ebeiedinone. Derivatization was carried out by esterification of the hydroxyl-containing Fritillaria alkaloids to the corresponding naphthoates with 1-naphthoyl chloride. Reaction conditions were optimized and the yields of the derivatization were between 94 and 100% for all test alkaloids. Derivatized alkaloids were characterized by mass spectrometry and HPLC-MS. The validated HPLC-UV method demonstrated linear UV response at the sampling ranges used, and a test limit of 1 microgram/mL was determined for all analytes. This analytical method is simple, convenient, and readily reproducible. The developed method was applied to the analysis of the major pharmacologically active alkaloids in three medicinally used Fritillaria species: F. cirrhosa, F. thunbergii, and F. hupehensis. Five major Fritillaria alkaloids were simultaneously analyzed qualitatively and quantitatively from crude extracts of each of these herbs.

Surgical management of axillary bromidrosis--a modified skoog procedure by an axillary bipedicle flap approach

We developed a modified Skoog procedure to treat axillary bromidrosis and hyperhidrosis that creates a bipedicle flap over the axillary fold with two parallel incisions to achieve a complete excision of the sweat glands. If necessary, the flap can be extended by making another parallel incision for a larger axillary hair-bearing area. Between 1988 and 1992, 110 patients were operated on using this method, but only 92 of the 110 patients, with an average follow-up period of 29.5 months, were available for this follow-up study. In this series, 86.9 percent of patients gave a family history of axillary bromidrosis. This follow-up review demonstrated that 93.5 percent of patients experienced no odor or occasional very mild axillary odor postoperatively. Postoperative scar formation was either nonvisible or excellent in 95.1 percent of patients, and 82.6 percent of patients reported either a hairless axilla or a marked decrease of axillary hair. Most importantly, 92.4 percent of patients reported a marked decrease in axillary sweat. Four axillary fossae developed postoperative subcutaneous hematomas, and six wounds had mild dehiscence. All of the wounds eventually healed satisfactorily after minor procedures. We concluded that for the treatment of extensive axillary apocrine bromidrosis, this new method achieves complete excision of the sweat glands and provides excellent functional and cosmetic results.

The immunological effect of 8-methoxypsoralen and UVA treatment on murine T-cell leukemia

8-Methoxypsoralen (8-MOP) plus long-wavelength UV radiation (UVA, 320-400 nm) have been used to treat various diseases such as cutaneous T-cell lymphoma, systemic scleroderma, rheumatoid arthritis and rejection of heart transplants. However, the immunological mechanism of this treatment remains unknown. In this report, we investigated the effect of 8-MOP/UVA on the modulation of the immunogenicity of a T-cell leukemia cell line (RL male 1 cells). The results demonstrated that the stimulator function of the in vitro 8-MOP/UVA-treated RL male 1 cells was enhanced in both RL male 1-specific allogeneic and syngeneic immune responses. Furthermore, the enhancement of the immunogenicity of the 8-MOP/UVA-treated RL male 1 cells was found to be strongly associated with the increase of intercellular adhesion molecule-1 expression on these 8-MOP/UVA-treated tumor cells. Therefore, our findings suggested that the alteration of the expression of the immune-related cell surface molecules might be an important effect of 8-MOP/UVA treatment on the elevation of the immunogenicity of the 8-MOP/UVA-treated tumor cells.

Human keratinocyte culture using porcine pituitary extract in serum-free medium

Extensive burn wound coverage remains a major problem in acute and reconstructive stages due to shortage of autologous skin donor sites. Many reports have described successful coverage of extensive burn wounds by using cultured keratinocytes sheet graft alone or overlaying a glycosaminoglycan substrate, allodermis or xenodermis. In our experience, the use of Boyce and Ham's serum-free medium made the preparation of keratinocyte cultures simple and the cell growth was prompt. In this study, one of the supplements in Boyce's culture medium, the bovine pituitary extract (BPE at concentration of 140 micrograms/ml), was replaced by different concentrations of fresh frozen porcine pituitary extract (PPE). The protein concentration of the original preparation of PPE was also 140 micrograms/ml but in which 375 +/- 21 pg/ml (1/10 dilution) of platelet-derived growth factor (PDGF) was detected by immunoassay (PDGF ELISA). Our results proved that PPE is an ideal supplement for the in vitro growth of keratinocytes, and when its protein concentration is 350 micrograms/ml will induce a significant keratinocyte growth by day 9 when compared to the regular BPE and also to the other concentrations of PPE (P < 0.05).

Disseminated tuberculomas in spinal cord and brain demonstrated by MRI with gadolinium-DTPA

Intramedullary tuberculoma is rare, and there has been no report of concurrent intramedullary and intracerebral tuberculomas. We report a 30-year-old man with miliary tuberculosis of the lung. He suffered sudden paraplegia due to tuberculomas in the thoracic spinal cord and MRI showed more tuberculomas in the cervical spinal cord, brain stem, and cerebral and cerebellar hemispheres. The tuberculomas were isointense on the T1-weighted images, and hyperintense on the T2-weighted images; there was marked enhancement with intravenous gadolinium-DTPA. All the tuberculomas were very small 1 year after antituberculous chemotherapy.

Effects of granulocyte-macrophage colony-stimulating factor and interleukin 6 on the growth of leukemic blasts in suspension culture

We examined the stimulatory effects of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 6 (IL)-6 on the in vitro proliferation of leukemic blast cells from patients with acute leukemia. Bone marrow or peripheral blood leukemic blast cells were obtained from 21 patients, including 14 cases of acute myeloblastic leukemia (AML), four cases of acute lymphoblastic leukemia (ALL), two cases of acute undifferentiated leukemia, and one case of acute mixed-lineage leukemia. The proliferation of leukemic blast cells was evaluated by measuring the incorporation of 3H-thymidine into cells incubated with various concentrations of cytokines for 3 days. GM-CSF stimulated the DNA synthesis (with greater than 2.0 stimulation index) of blast cells in 9 of 14 (64%) AML cases, two cases of acute undifferentiated leukemia and one case of acute mixed-lineage leukemia. Only two cases of AML blasts responded to IL-6 to grow in the short-term suspension cultures. GM-CSF and IL-6 did not display a synergistic effect on the growth of leukemic cells. Moreover, GM-CSF and IL-6 did not stimulate the proliferation of ALL blast cells. Binding study also revealed the specific binding of GM-CSF on the blast cells of acute undifferentiated leukemia and acute mixed-lineage leukemia. Our results indicated that leukemic blast cells of acute undifferentiated leukemia and acute mixed-lineage leukemia possessed functional GM-CSF receptors.

The effect of recombinant human erythropoietin on hemostatic status in chronic uremic patients

The hemostatic effects of recombinant human erythropoietin (rHuEP) were investigated in 20 patients with end-stage renal disease (thirteen on hemodialysis, seven without dialysis) receiving this hormone. We studied their hemograms and coagulation profiles before and at 1 month after initiation of rHuEP therapy. One month after rHuEP administration, improvement in anemia (16/20, 80%) and shortening of bleeding time (17/19, 89.5%) were observed. Shortening or correction of bleeding time was achieved in three patients without any increase of the hemoglobin level. This means that factors other than the increased hematocrit level might contribute to shortening bleeding time in uremic patients receiving rHuEP treatment. The platelet count, prothrombin time, partial thromboplastin time, and fibrinogen level did not change over the course of rHuEP therapy. Thrombosis of vascular access was not observed, and heparin doses were not increased in this short-term period. A significant decrease was found in the plasminogen level, from 108.5% to 88.2% (p less than 0.05), in uremic patients on hemodialysis. The antithrombin III level also decreased, from 98.8% to 89.8% (p less than 0.05), and its level dropped to below normal ranges in six of thirteen patients (46%) on hemodialysis after treatment with rHuEP. No significant change was noted in the levels of antithrombin III, plasminogen, and alpha 2-antiplasmin in uremic patients not receiving dialysis. These results suggest that rHuEP administration induces increased extracorporeal dialyzer clotting and consumption coagulopathy, and that this extracorporeal consumption coagulopathy may play a role in the genesis of thrombotic complications.

A novel -32 (C-A) mutant identified in amplified genomic DNA of a Chinese beta-thalassemic patient

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Internal carotid artery occlusion in painful ophthalmoplegia

Two patients with left painful ophthalmoplegia, caused by infiltrating lesion in left superior orbital fissure and/or cavernous sinus, subsequently developed left cerebral infarction associated with occlusion of the proximal portion of left internal carotid artery demonstrated by CT and angiogram. It thus is worthy to remind that painful ophthalmoplegia may have the possibility of resulting in cerebral infarction associated with carotid occlusion.

Atypical presentations of tuberculous meningitis--a case report

A case of tuberculous meningitis, proved by cerebrospinal fluid (CSF) cultures, is reported due to atypical findings in CSF. This 19-year-old man developed subacute headache and fever for 2 weeks, followed by focal seizure and left hemiparesis. Initial CSF study showed hemorrhagic lymphocytic pleocytosis with mildly elevated protein and normal sugar content, mimicking viral or postinfectious meningoencephalitis. Follow-up CSF studies showed polymorphonuclear pleocytosis. A concomitant bacterial meningoencephalitis was suspected, though repeated CSF cultures did not isolate any bacteria. The activity of adenosine deaminase in CSF was 12 U/L, highly suggestive of tuberculous meningitis. Magnetic resonance imaging (MRI) showed only a focal meningoencephalitis in the right lateral frontal cortex. Due to progressive deterioration of the clinical status, umbrella therapy, including antimycobacterial drugs and strong antibiotics were given. At a later time, growth of tubercle bacilli was reported in the CSF cultures. Follow-up study of MRI 4 months later, showed thick abnormal enhancement in the basal cisterns and obstructive hydrocephalus, typical findings of chronic basal meningitis.

Distribution of cerebral infarcts on computed tomography

Locations of cerebral infarcts on computed tomography were analyzed on all patients admitted for ischemic stroke or status lacunaris in 1984. Patients who had only one symptomatic infarct, without histories of strokes or transient ischemic attacks, were allocated to group A, the rest made up group B. Group A showed that 47.6% of symptomatic infarcts were lacunes with similar percentages in the following areas: lenticular nucleus (12.7%), internal capsule (12.7%), and subcortical white matter (11.1%). In group A, the cortex (49.2%) was the most common site of infarction, while in group B, it was the subcortical white matter (31.7%). However, if the structures supplied by the basal perforating arteries (basal ganglia, thalami, and internal capsules) were considered as a whole, this area (41.8%) was the most common site for infarcts in group B. Thus, asymptomatic infarcts and those of status lacunaris contributed greatly to the overall distribution of cerebral infarcts.

Timed overnight sodium and potassium excretion and blood pressure in steel workers in North China

Three timed overnight urinary sodium (Na), potassium (K) and creatinine measurements, standardized to 8 h, as well as three blood pressures on corresponding consecutive days were obtained on a sample of 90 steel workers (40 men, 50 women) aged 34-56 years in Beijing, North China. For three indices of electrolyte excretion - absolute Na and K output/8 h, Na:K ratio and 8 h creatinine output - the ratios of intra- to inter-individual variations were less than 1.0 for men, but higher for women in contrast to findings for U.S. population groups of similar age. This fact, probably reflecting greater stability of day to day electrolyte intake by Chinese than Americans, enables reasonably precise characterization of dietary electrolyte intakes of individual Chinese, particularly men, with only a few timed overnight urine specimens. With 3-day mean values for each person, nominally significant (i.e. not adjusted for multiple testing) positive simple correlations were found for urinary Na, Na:K and Na:creatinine with blood pressure [both systolic (SBP) and diastolic (DBP)] for men; and women for Na:K with SBP and DBP, but Na:creatinine with SBP only. With control for age, body mass index and pulse in multivariate analyses, only the relationship of Na:K and Na:creatinine to SBP and DBP remained significant for men; a similar, though less strong and consistent, trend was found for women, and K was inversely related to SBP for women. These data are consistent with an association between habitual intake of sodium and risk of hypertension, and also suggest that habitual potassium intake may have a countervailing influence in this regard.

Determination of Indole-3-acetic Acid in Douglas Fir Using a Deuterated Analog and Selected Ion Monitoring: Comparison of Microquantities in Seedling and Adult Tree

Indole-3-acetic acid (IAA) content in shoot tips of Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) trees and seedlings was determined by combined gas chromatography-mass spectrometry using a deuterated analog (d(2)-IAA) as an internal standard and the technique of selected ion monitoring. Ratios of the peak heights of the deuterated analog internal standard to endogenous IAA revealed a slightly higher content of IAA in seedlings compared with the shoot tips collected in June. The relatively high level of IAA (2.9 micrograms per gram fresh weight) in seedlings is discussed in relation to in vitro propagation of this species.

Regeneration of Douglas Fir Plantlets Through Tissue Culture

Douglas fir plantlets were produced in tissue culture under defined conditions from cotyledon explants obtained from 2- to 4-week-old seedlings. Tissue pieces were cultured on the surface of a fabric tissue support (100 percent polyester) saturated with liquid nutrient medium; this facilitated periodic changes of the medium to meet the requirements at successive developmental stages without transfer of cultured tissues. Plant growth regulators were needed to stimulate adventitious bud formation. Plantlets were regenerated by rooting excised shoots at 19 degrees C on agarsolidified medium containing sucrose and the auxin naphthalene-2-acetic acid. After root initiation, plant growth regulators were removed; this resulted in stimulation of root elongation and the subsequent development of plantlets, which were then established in soil.

Organogenesis from Callus Culture of Hordeum vulgare

Rapidly proliferating callus cultures from the apical meristem of Hordeum vulgare L., cultivars "Himalaya" and "Mari", were established on a defined medium supplemented with auxin and cytokinin. A frequency of organ differentiation of ca. 85% was obtained by transfer to the same medium but without any growth regulators. All regenerated plants had the diploid chromosome number of 14 (2n).

The influence of genomes on autonomous growth of pith cultures of Nicotiana glauca-Langsdorffii hybrids

A differential influence of the two parental genomes on cell proliferation and morphogenesis in pith tissue explants can be observed among the various tumorous hybrid combinations between Nicotiana glauca Grah. and N. langsdorffii Weinm.: the F1 hybrid (GL), its amphiploid (GGLL), and two different triploids (GGL and GLL). This influence was evident when the explants were cultured in the presence of exogenous auxin (indole-3-acetic acid, 2.5 μM), supplied either continuously or for a brief period of time. Compared with the F1 and the amphiploid, the higher proportion of N. glauca genomes in GGL cells resulted in greater growth, the higher proportion of N. langsdorffii genomes in GLL cells in lesser growth. In addition, shoots are produced on the GGL callus, while only roots are formed on calli of the other types in the same medium. When, in addition to auxin, a cytokinin [6-(3-methyl-2-butenyl-amino)purine] was added to the culture medium, the differential growth of the different tissue types was less pronounced; at 1.0 μM of the cytokinin, all tissues grew at about the same rate and remained undifferentiated, regardless of their genomic composition.

Induction of indoleacetic Acid synthetases in tobacco pith explants

Formation of indoleacetic acid synthetases in tobacco pith explants was determined by following the growth of tissue cultures under conditions of indole-3-acetic acid (IAA) deprivation and by measuring the enzymatic conversion of tryptophan to IAA in the cultures. The pith explants obtained from the parent plant (Nicotiana glauca) and from basal regions of the tumor-prone hybrid (N. glauca x N. langsdorffii) both show a requirement for exogenous IAA for growth initiation in culture. The parent pith requires the constant presence of added IAA for continued growth, but hybrid pith, after initial treatment with IAA, will grow without further additions. IAA synthetases are detected in the cell homogenates of hybrid pith explants cultured with either continuous or initial IAA addition. These observations indicate that IAA may induce its own production. In contrast, IAA synthetases are not found in the parent pith under comparable culture conditions. Besides IAA, nonhormonal compounds such as indole and tryptophan are also capable of stimulating growth of hybrid pith, possibly through the induction of IAA synthetases needed for IAA formation. Indole and tryptophan are, however, inactive in growth promotion of the parent pith. These results suggest that the genomic expression of IAA synthetase formation is more stringently controlled in N. glauca than in the tumorprone hybrid.

Evolution of the transcription unit of ribosomal RNA

In eukaryotes the two principal RNA components of the ribosomes are initially synthesized as a large complex precursor molecule, which may be thought of as a transcription unit. The precursor is converted, via intermediates, to the mature forms of ribosomal RNA (rRNA). In order to assess the extent of variation in the size of this rRNA transcription unit among different organisms, and to infer its possible mode of evolution, we have determined its molecular weight in several selected species. Pulse-labeled and long-term labeled RNA's were extracted from various types of cells, and analyzed by electrophoresis on acrylamide gels. Identification of particular components as rRNA precursors was made according to several stated criteria. Our results, together with an analysis of previously published data, suggest that in plants and lower animals, up to and including reptiles, the unit of transcription of rRNA is a 2.7-2.8 million dalton molecule, which is only about 25 per cent larger than its combined rRNA products. In contrast, birds, marsupials and placental mammals, exhibit a seemingly less economical form of rRNA synthesis. Their transcription units are 4.0-4.2 million daltons, about 80 per cent larger than the rRNA products. In the organisms with the smaller transcription unit the major intermediate precursor of rRNA is 1.5-1.6 million daltons, as compared to 2.0-2.2 million daltons in birds and mammals. The significance of these findings is discussed in relation to evolutionary changes in the base composition of the ribosomal RNA genes.