In vitro recombination of bacteriophage T7 DNA detected by a direct physical assay

We developed a simple, direct, physical assay to detect genetic recombination of bacteriophage T7 DNA in vitro. In this assay two mature T7 DNA molecules, each having a unique restriction enzyme site, are incubated in the presence of a cell-free extract from T7-infected Escherichia coli cells. After extraction of the DNA, restriction enzyme digestion, and agarose gel electrophoresis, genetic recombination is detected by the appearance of a novel recombinant DNA band. Recombination frequencies as high as 13% have been observed. We used this assay to determine the genetic requirements for in vitro recombination. In agreement with results obtained previously with a biological assay, T7 recombination in vitro appears to proceed via two distinct pathways.

Stiffness and inelastic deformation in acrylictitanium composite implant materials under compression

A variety of acrylic bone cement-metal composite materials were prepared and tested in simple compression at 37 degrees C in order to evaluate the mechanical behavior of these materials for possible use in bone replacement. The stiffness of the composite was of particular concern, and a simple rule of mixture was used to raise the modulus of acrylic bone cement. The reinforcement of the cement was accomplished by titanium and Ti-6Al-4V in different forms, e.g., wire, sheet, wire mesh, and powder. Test results demonstrated that the stiffness of the bone cement could indeed be increased by a desired amount to that of bone. A 16% volume fraction consisting of 25 0.10 cm diam Ti-6Al-4V wires increased the modulus of the bone cement by 380% to a value comparable to the modulus of cortical bone. Titanium sheet was nearly as effective as wires in increasing the modulus of bone cement, while titanium mesh was not a significantly effective reinforcing material. The amount of titanium powder added to the bone cement did not alter the compliance of the matrix material. In addition, as the flow strength increased, the strain to the point of load instability decreased. It was concluded that the extent of stiffening was governed by nonuniform deformation in the metal and the adjacent matrix which could be explained on the basis of geometrical considerations. Some of the limitations of the test results as well as methods of predicting the composite implant material behavior are also outlined.

Lithocholic acid-induced cholestasis in newborn rats

Susceptibility to lithocholic acid-induced cholestasis was examined in developing rats aged 14, 21 and 70 days. After bile duct cannulation, bile was collected for 30 min prior to, and 120 min following an i.v. injection of [14C]lithocholic acid (LCA). The liver weight/body weight ratio of newborns was significantly smaller than that of adults (3.13 +/- 0.09 at 14 days vs. 4.76 +/- 0.20 at 70 days). Therefore, when the LCA dosage was calculated per g body weight, the livers of newborns were exposed to larger amounts of LCA. The dosage was then given per liver/body weight ratio for an accurate comparison with adults. Bile flow was reduced by 7-18% in newborns, while a maximum decrease of 90% was recorded in adults by 2 h post injection, the latter drop in bile flow being proportional to LCA retention in the liver. In contrast, LCA retention was minimal in young rats with 91-95% of it being excreted via the bile. The decreased susceptibility of newborns to cholestasis appears to be related to their capacity to excrete LCA.

Infiltrating lobular carcinoma of the breast: an evaluation of the incidence and consequence of bilateral disease

A histological review of 1003 invasive breast carcinomas identified 103 patients with infiltrating lobular carcinoma, for whom clinical and survival data were collected in each case. Six patients had bilateral carcinoma at diagnosis and 14 developed a contralateral carcinoma during the period of follow-up. The major factor predicting patients at risk of developing a contralateral carcinoma was histological type. Analysis of survival data on the patients with bilateral disease showed poor survival in the group with synchronous bilateral disease, but no difference in survival between patients with metachronous bilateral and unilateral disease. This suggests that the development of a metachronous contralateral carcinoma does not necessarily reduce the probability of survival of patients with infiltrating lobular carcinoma.

Prevalence and diagnosis of laboratory animal allergy

A survey of the prevalence of laboratory animal allergy to rats, mice, guinea pigs and rabbits among sixty-nine animal workers and 308 other subjects on a pharmaceutical research site revealed a 22% prevalence of laboratory animal allergy among the animal workers. The overall prevalence of atopy was 67% in persons with allergy to laboratory animals. This was significantly greater than the 31% prevalence in other animal workers. Skin-prick tests and specific IgG and IgE assays to urinary protein extracts strongly correlated with the occurrence of laboratory-animal allergy and would appear to have diagnostic value. However, a number of clinically diagnosed laboratory-animal-allergy subjects gave no evidence of immunological response to the urinary allergens and wider diagnoses may have to be applied in these cases.

Invasive cribriform carcinoma of the breast

A histological review of 1003 invasive breast carcinomas identified 51 tumours in which the invasive component showed a predominantly cribriform pattern. These separated into two groups; 35 which showed exclusively cribriform or cribriform with a limited extent of tubular invasive elements only, designated 'classical' invasive cribriform carcinoma and 16 which also contained areas of less well differentiated invasive carcinoma, designated 'mixed' invasive cribriform carcinoma. At follow-up, 10 to 21 years after diagnosis, none of the 35 patients with classical invasive cribriform carcinoma had died as a result of this initial carcinoma and 30 remained alive. Of the 16 remaining patients, whose tumours showed areas of less well differentiated carcinoma, only six remained alive. However, the adjusted 10 years survival rate of these patients in this mixed group was significantly better than that of invasive carcinoma in Edinburgh. Invasive cribriform carcinoma in its classical form, is a histological subgroup of invasive carcinoma with the same excellent prognosis as that of invasive tubular carcinoma.

Interference in the radioallergosorbent test by antibody light chains in rabbit urine

Immunological techniques have been used to identify and quantitate rabbit antibody light chains in the urine of rabbits. The influence of these light chains on the radioallergosorbent test (RAST) used for the diagnosis of laboratory animal allergy to rabbit urinary protein allergens is described. The presence of IgG antibody specific for rabbit derived antigens in human serum has been confirmed.

The impact of support for black adolescent mothers

This exploratory study focused on the association between social support and adolescents' responses to early motherhood. Subjects were 64 Black adolescent mothers in three groups (High School, Program, and Dropout). Structured interviews were used to assess the young mothers' emotional stress as well as the amounts, sources, and kinds of support available. Self-esteem and sense of control were assessed via standarized instruments. A major finding was that support from individuals is related to a decrease in stress and an increase in self-esteem. The results are discussed in relation to the growing body of research documenting the impact of such support on maternal role performance.

The development and validation of radioallergosorbent tests for the detection of specific human IgE antibody directed against laboratory animal urinary proteins

Radioallergosorbent tests (RAST) using urinary proteins from mice, rats, guinea pigs and rabbits have been developed and used in the diagnosis of laboratory animal allergy (LAA). Of the 273 subjects tested, 15 had been previously diagnosed as laboratory animal allergic and 8 of these (53%) gave one or more positive RAST results. Of the 258 symptom-free individuals, only 9 (3.5%) had one or more positive RAST. Of these 9, 7 had previously worked with animals or had occupational exposure to the appropriate species; the remaining 2 individuals had only some pet exposure. RAST was, therefore, of value in the diagnosis of LAA. During the development of these RAST assays, several sources of potential error were identified. Modest titres of total IgE (600 IU/ml and above) were found to influence the specific RAST index observed and lead to false positive results. The presence of human IgG antibody specific for rabbit serum proteins was also identified in four sera, and was responsible for interference in the rabbit urinary protein RAST system.

Estrogen receptor status in inflammatory breast carcinoma

Sixteen women with a clinical diagnosis of inflammatory breast carcinoma had estrogen receptor analysis performed. Eleven of 16 were premenopausal. Median age of all patients was 46 years. All patients had estrogen receptor (ER) assay by either dextran charcoal method or by sucrose gradient method. Five patients were ER + ( greater than or equal to 10 fmol/mg cytosol protein) and 11 were ER -, with almost no binding at all. Response to therapy for metastatic disease using either hormones or chemotherapy was disappointing.

alpha 1-Proteinase inhibitor production by human adenocarcinomas xenotransplanted into nude mice

Human colon adenocarcinomas xenotransplanted into BALB/c nude mice were examined for the ectopic synthesis of alpha 1-proteinase inhibitor(s) (alpha 1Pi). Tumor extracts were prepared by homogenization followed by molecular sieve chromatography on Sepharose 4B. Fractions with immunoreactive alpha 1Pi were concentrated and adsorbed onto a concanavalin A-Sepharose 4B affinity column, then eluted, concentrated, and analyzed. All 4 colon tumors examined produced alpha 1Pi with full antigenic identity to normal human plasma alpha 1Pi. Electrophoretic mobilities of 3 of the tumor-derived alpha 1Pi were different from the electrophoretic mobility of the normal human plasma alpha 1Pi. Activities of the inhibitors were determined by the reaction of each tumor extract with pancreatic elastase (PE) followed by immunoelectrophoresis of the reaction mixture against both anti-human alpha 1Pi and anti-PE antisera. Two of the tumor-derived alpha 1Pi examined were active in inhibiting PE.

Preoperative intraparietal (intra-incisional) cefoxitin in abdominal surgery

The effect of preoperative intraparietal (intra-incisional) injection of cefoxitin along the site of the intended incision on the incidence of wound infection has been investigated by a randomized prospective study of 181 consecutive patients undergoing abdominal surgery. A significant reduction in wound infection was evident in the cefoxitin-treated group (4.4 per cent) when compared with controls (16.7 per cent) (chi 2 = 6; P = 0.02). Administration of antibiotic by this route did not delay wound healing or produce any undesirable sequelae.

Suppression of lymphocyte activation by a protein released from isolated perfused rat liver

Isolated rat liver perfusates contain a substance which inhibits 3H-thymidine uptake by phytohemagglutinin-stimulated human peripheral blood lymphocytes in a dose-dependent, noncytotoxic fashion. Suppression is not due to interference of lymphocyte-phytohemagglutinin interaction or dilution of the thymidine pool. Complete inhibition of thymidine uptake is achieved with less than 1.0 microgram of material per ml (which is a potentially achievable concentration in vivo). The release of this material is directly and quantitatively associated with hepatocellular injury as measured by release of glutamic pyruvate transaminase. The material is a highly basic protein with a molecular weight of approximately 65,000 to 80,000 daltons. It is a product of the hepatocyte rather than of nonparenchymal liver cells. Liver-derived materials, such as the presently described molecule, may play a role in in situ regulation of lymphocyte function during immunologically mediated liver disease.

Clonal expression of the Tn antigen in erythroid and granulocyte colonies and its application to determination of the clonality of the human megakaryocyte colony assay

To evaluate whether exposure of Tn determinants at the surface of human erythrocytes, platelets, and granulocytes could arise from a somatic mutation in a hemopoietic stem cell, burst-forming unit erythroid (BFU-E) colonies, colony-forming unit granulocyte-macrophage (CFU-GM), and colony-forming unit-eosinophil (CFU-Eo) were grown from a blood group O patient with a typical Tn syndrome displaying two distinct populations (Tn(+) and Tn(-)) of platelets, granulocytes, and erythrocytes. A large number of colonies was observed. Individual colonies were studied with a fluorescent conjugate of Helix pomatia agglutinin (HPA). A sizeable fraction of each of the erythroid and granulocytic colonies appeared to consist exclusively of either HPA-positive or HPA-negative cells, thereby demonstrating the clonal origin of those exhibiting the Tn marker. Similar results were obtained from a second patient. These findings establish that the HPA labeling of Tn cells is an accurate marker permitting assessment of the clonality of the human megakaryocyte (MK) colony assay. For the study of MK cultures a double-staining procedure using the HPA lectin and a monoclonal antiplatelet antibody (J-15) was applied in situ to identify all MK constituting a colony. Our results, obtained in studies of 133 MK colonies, provide definitive evidence that the human MK colony assay is clonal because all MK colonies were exclusively composed of Tn(+) and Tn(-) MK. Furthermore, the distribution of MK within a single colony was shown to be seminormal with a mean at 6 MK, isolated MK typically being absent in culture. Comparison of the proportion of mature Tn(+) cells in blood with their respective Tn(+) progenitors has also shown that no proliferative advantage occurs after the commitment; because Tn polyagglutinability is an acquired disorder, then the expansion of the Tn(+) clone must occur either during the proliferative stage of the pluripotent stem cell or during the commitment itself. This study therefore affords evidence that a blood group antigen plays a role in the differentiation of a pluripotent stem cell.

A simplified model for heterotopic rat heart transplantation

A technique for simplified heterotopic rat heart transplantation having only aorto-aortic anastomosis is presented. The heterotopic rt heart survives and functions well when one lung lobe is attached t the transplantation and functions as a reservoir. Iso- and allotransplants are compared by electrocardiogram (ECG) determination and histological examination. Isotransplants exhibited normal heart and lung throughout the 6-month observation period. allotransplants ceased to function by the 16th postoperative day, with the cessation of palpable heart beat over the abdominal wall by the 10th postoperative day. This simplified heterotopic rat heart transplantation model can be operated by nonsurgeons in an unhurried manner with minimal training in microvascular surgery, and can be applied to various transplantation immunological studies.

The use of doxapram in the prevention of postoperative pulmonary complications

A prospective, double-blind, randomized controlled clinical trial has been conducted to assess the effect of doxapram hydrochloride infusions on pulmonary complications in patients undergoing extensive abdominal operations. For the purposes of this study, a pulmonary complication was defined as the production of purulent sputum or the presence of any abnormal clinical or roentgenologic chest signs. Of the 53 control patients, 41 had chest problems develop by these criteria, whereas the same was true of only 20 of the 40 patients receiving doxapram. The average duration of hospitalization was one day less for those receiving the drug.

Infiltrating lobular carcinoma of the breast

On review of the histology of 1050 primary breast carcinomas, 103 cases of infiltrating lobular carcinoma were identified and clinical and survival data collected in each case. The tumours were then separated into four groups on the basis of histological pattern and these groups shown to have significantly different survival times. Assessment of the presence of in situ carcinoma, elastosis and intracytoplasmic lumina was performed in each case and the effect of these features on survival investigated. In addition to stage of disease at presentation, the major significant factor in predicting survival of patients with this type of invasive carcinoma is histological type.

Influence of morphinization on the development of isoenzymes of pyruvate kinase in rat liver

1. Acute administration or morphine to foetuses and neonates either directly or via the mother leads to a decrease in the total pyruvate kinase activity. 2. The L-type isoenzyme is selectively suppressed while the M-type isoenzyme is not altered to any significant extent with a consequent lowering of the L/M ratio. 3. The decrease in the total pyruvate kinase activity and the L/M ratio is more prominent when the route of administration of morphine is via the mother. 4. The possible explanation for this difference in the route of administration is that morphine can be converted into a more active metabolite with greater biological potency in adult animals.

Development and use of radioimmunoassays for the detection of human IgG antibodies to laboratory animal urinary proteins

A radioimmunoassay method for the detection of human IgG antibodies to laboratory animal urinary proteins has been developed using partially purified protein fractions prepared from crude urine extracts by gel filtration. The proteins from the four species, mouse, rat, guinea pig and rabbit, were labelled with 125I and used in an antigen binding assay employing a sepharose-linked staphylococcal protein A immunosorbent. Results, expressed as arbitrary units of specific IgG per unit serum, show antibodies to one or more species present in 57% of current animal workers compared with 6% of non-animal workers.

Genetic recombination of bacteriophage T7 in vivo studied by use of a simple physical assay

A new physical method was developed to assay genetic recombination of phage T7 in vivo. The assay utilized T7 mutants that carry unique restriction sites and was based on the detection of a new restriction fragment generated by recombination. Using this assay, we reexamined the genetic requirements for recombination of T7 DNA. Our results were in total agreement with previous findings in that recombination required the products of genes 3 (endonuclease), 4 (primase), 5 (DNA polymerase), and 6 (exonuclease). Recombination was found to be independent of DNA ligase and DNA packaging and maturation functions.

Secretion of alpha 1-proteinase inhibitor by cultured rat alveolar macrophages

Alpha 1-proteinase inhibitor, metabolically labeled with 35S, was detected in concentrated culture medium of rat alveolar macrophages by immunoelectrophoresis autoradiography. The metabolically labeled macrophage alpha 1-proteinase inhibitor had the same electrophoretic mobility as did pure rat serum alpha 1-proteinase inhibitor. Moreover, monospecific antiserum to rat serum alpha 1-proteinase inhibitor precipitated a 35S-labeled protein from macrophage culture supernates, and this protein was shown by sodium dodecyl sulfate polyacrylamide gel electrophoresis to have a molecular weight close to that of rat serum alpha 1-proteinase inhibitor. Cycloheximide (an inhibitor of protein synthesis) at a concentration of 0.50 micrograms/ml, inhibited secretion of labeled inhibitor. This, cultured rat alveolar macrophages secrete detectable concentrations of a proteinase inhibitor believed to play a major role in lung defense.

Psychotic exacerbation with haloperidol

A case illustrating the worsening of a patient's schizophrenic symptoms following haloperidol dosage increases in presented. This case is remarkable in that few cases of psychotic exacerbation with haloperidol dosage increases have been reported in the world literature. The possibility exists that, like certain tricyclic antidepressants, neuroleptic medication may possess a "therapeutic window,". The concept of a therapeutic window and its relationship to the phenomenon of psychotic exacerbation is reviewed. In evaluating this condition, the clinician should consider other causes of psychotic exacerbation, such as akathisia and anticholinergic psychosis.

Volvulus of the transverse colon

Volvulus of the transverse colon is rare. Seven cases, 6 acute, are presented. Early diagnosis and prompt surgical management prevented complications. At laparatomy, extended right hemicolectomy or end colostomy and distal mucous fistula are the procedures of choice. Non-resection was associated with recurrence in three cases.

Performance evaluation of image-intensifier tubes

A series of image quality measurements were obtained over a two-year period for eight image-intensifier tube fluoroscopic units used in clinical practice. The measurements were in agreement with a radiologist's opinion of the image quality for each tube. The results showed that some systems did not change significantly over the two-year period, while others deteriorated from acceptable to unacceptable image quality during this time. For this reason, it is recommended that measurements be obtained for all diagnostic fluoroscopic equipment at least semiannually to monitor image quality and remedy any changes before diagnostic accuracy is severely affected.

The management of acute sigmoid volvulus

One hundred and thirty-four patients with acute sigmoid volvulus are analysed. When the diagnosis is made preoperatively, decompression per rectum is effective in 85 per cent of cases, and should be the initial treatment of choice unless gangrene of the bowel is suspected. In this situation emergency laparotomy should be performed and where gangrenous bowel is confirmed a Hartmann resection appears to be associated with a low mortality and least complications. When the sigmoid loop is found to be viable, it should still be resected. The merits and pitfalls of various procedures in this situation are discussed.

Non-uniform swelling properties of the corneal stroma

The swelling properties of the anterior and posterior stroma of bovine and rabbit corneas were examined by three different methods. The results show that the posterior stroma can swell more than the anterior stroma. Also, at a given swelling pressure, the posterior stroma is more hydrated than the anterior stroma. In a third experiment it is demonstrated that the posterior stroma is also more hydrated in the living eye. It is concluded that the stroma is not a homogeneous structure. The superficial stroma has different physiological properties from the deep stroma. These differences must be taken into account in theoretical models of corneal deturgescence.