The high transforming potency of erbB-2 and ret is associated with phosphorylation of paxillin and a 23 kDa protein

Two-dimensional gel maps of proteins phosphorylated by the epidermal growth factor receptor (EGFR) and erbB-2 kinases were obtained, to investigate the molecular basis of the different biological properties of these two molecules. Several proteins were phosphorylated by EGFR or erbB-2 with different stoichiometry. Differences were either quantitative or qualitative. In NIH3T3 cells, erbB-2 is 100-fold more transforming than EGFR. In the same cell line several proteins were preferentially phosphorylated by erbB-2, as compared to EGFR. To identify which of these substrates might be directly involved in mitogenic signaling, we obtained two-dimensional maps of proteins phosphorylated on tyrosine by EGFR/ret and an EGFR/erbB-2TK chimeric receptors. Both these chimerae behaved indistinguishably from erbB-2 in a number of bioassays and potently transformed NIH3T3 cells. Paxillin and a 23 kDa substrate were invariably phosphorylated to higher stoichiometry whenever potent mitogenic and transforming signals were activated. We propose that paxillin and the 23 kDa substrate are important elements in the erbB-2 and ret-activated mitogenic and transforming signaling.

Evolutionary conservation of the EPS8 gene and its mapping to human chromosome 12q23-q24

We have previously isolated the coding sequence for a novel substrate for tyrosine kinases, eps8, from NIH3T3 fibroblasts. Eps8 was phosphorylated in vivo by several receptor tyrosine kinases (RTKs) and, upon overexpression, was able to enhance EGFR-mediated mitogenic signaling in NIH3T3 cells. To gain understanding of eps8 function as well as its role in normal and neoplastic proliferation, we cloned the human eps8 coding sequence and studied expression of the human RNA and protein, evolutionary conservation, and chromosomal location. In addition to a previously identified SH3 domain, the predicted amino acid sequence of human eps8 revealed a non-random distribution of prolines, clustered in a way to suggest SH3-binding sites and a putative PH domain. Eps8 was expressed in all epithelial and fibroblastic lines examined and in some, but not all, hematopoietic cells. An essential function of eps8 in cell growth regulation was underscored by its conservation during evolution, where eps8-related sequences were detected as early as in Saccharomyces cerevisiae. Finally, the human EPS8 locus was mapped to chromosome 12q23-q24.

Tracheal laceration from endotracheal intubation in a cat

Iatrogenic trauma to the upper airway as a result of the clinical use of endotracheal tubes has rarely been reported in domestic animals. This report describes a case of tracheal laceration in a cat after endotracheal intubation for a dental procedure under general anaesthesia. The diagnosis and successful management of the condition are discussed, and other complications of the use of cuffed endotracheal and tracheostomy tubes are considered.

The human eps15 gene, encoding a tyrosine kinase substrate, is conserved in evolution and maps to 1p31-p32

Employing an expression cloning approach for tyrosine kinase substrates, we have previously isolated the coding sequence for a novel putative EGFR substrate, eps15, from NIH3T3 fibroblasts. Eps15 displayed a receptor-specific pattern of tyrosine phosphorylation in vivo and was able to transform NIH3T3 cells upon overexpression. To gain understanding of eps15 function as well as its role in normal and neoplastic proliferation, we cloned the human eps15 coding sequence and studied expression of the human RNA and protein, evolutionary conservation, and chromosomal location. The close structural similarity of human eps15 with the murine homologue is indicated by 89% and 90% identity of nucleotide and predicted amino acid sequences, respectively. Using the human eps15 coding sequence as probe, we demonstrate that eps15 is member of a gene family that is highly conserved during evolution. An essential function of eps15 in cell growth regulation is underscored by our observation of ubiquitous expression at the transcript and the protein level in normal and malignant human cells. The human EPS15 locus maps to chromosome 1p31-p32, a region involved in deletion in neuroblastoma, translocations in acute lymphoblastic leukemia, and exhibiting a fragile site.

Symphyseal distraction-osteotomy using an ulnar autograft for the treatment of pelvic canal stenosis in three cats

Three adult cats with obstipation due to stenosis of the pelvic canal were treated by symphyseal distraction-osteotomy using an ulnar autograft. The duration of clinical signs before the surgery in the three cats was one, three and 19 months; the first two cats had no recurrence of signs after surgery, and the third had less severe and less frequent bouts of constipation.

An epidermal growth factor receptor/ret chimera generates mitogenic and transforming signals: evidence for a ret-specific signaling pathway

A chimeric expression vector which encoded for a molecule encompassing the extracellular domain of the epidermal growth factor (EGF) receptor (EGFR) and the intracellular domain of the ret kinase (EGFR/ret chimera) was generated. Upon ectopic expression in mammalian cells, the EGFR/ret chimera was correctly synthesized and transported to the cell surface, where it was shown capable of binding EGF and transducing an EGF-dependent signal intracellularly. Thus, the EGFR/ret chimera allows us to study the biological effects and biochemical activities of the ret kinase under controlled conditions of activation. Comparative analysis of the growth-promoting activity of the EGFR/ret chimera expressed in fibroblastic or hematopoietic cells revealed a biological phenotype clearly distinguishable from that of the EGFR, indicating that the two kinases couple with mitogenic pathways which are different to some extent. Analysis of biochemical pathways implicated in the transduction of mitogenic signals also evidenced significant differences between the ret kinase and other receptor tyrosine kinases. Thus, the sum of our results indicates the existence of a ret-specific pathway of mitogenic signaling.

Eps8, a substrate for the epidermal growth factor receptor kinase, enhances EGF-dependent mitogenic signals

A method which allows direct cloning of intracellular substrates for receptor tyrosine kinases (RTKs) was developed. By applying this technique to the study of the epidermal growth factor receptor (EGFR) signaling pathway, we have isolated a cDNA, designated eps8, which predicts a approximately 92 kDa protein containing an SH3 domain. Eps8 also contains a putative nuclear targeting sequence. Antibodies specific to the eps8 gene product recognize a protein of M(r) 97 kDa and a minor 68 kDa component, which are closely related, as demonstrated by V8 proteolytic mapping. The product of the eps8 gene is tyrosine-phosphorylated in vivo following EGF stimulation of intact cells and associates with the EGFR, despite the lack of a functional SH2 domain. Several other RTKs are also able to phosphorylate p97eps8. Thus, the eps8 gene product represents a novel substrate for RTKs. Adoptive expression of the eps8 cDNA in fibroblastic or hematopoietic target cells expressing the EGFR resulted in increased mitogenic response to EGF, implicating the eps8 gene product in the control of mitogenic signals.

eps15, a novel tyrosine kinase substrate, exhibits transforming activity

An expression cloning method which allows direct isolation of cDNAs encoding substrates for tyrosine kinases was applied to the study of the epidermal growth factor (EGF) receptor (EGFR) signaling pathway. A previously undescribed cDNA was isolated and designated eps15. The structural features of the predicted eps15 gene product allow its subdivision into three domains. Domain I contains signatures of a regulatory domain, including a candidate tyrosine phosphorylation site and EF-hand-type calcium-binding domains. Domain II presents the characteristic heptad repeats of coiled-coil rod-like proteins, and domain III displays a repeated aspartic acid-proline-phenylalanine motif similar to a consensus sequence of several methylases. Antibodies specific for the eps15 gene product recognize two proteins: a major species of 142 kDa and a minor component of 155 kDa, both of which are phosphorylated on tyrosine following EGFR activation by EGF in vivo. EGFR is also able to directly phosphorylate the eps15 product in vitro. In addition, phosphorylation of the eps15 gene product in vivo is relatively receptor specific, since the erbB-2 kinase phosphorylates it very inefficiently. Finally, overexpression of eps15 is sufficient to transform NIH 3T3 cells, thus suggesting that the eps15 gene product is involved in the regulation of mitogenic signals.

The ezrin-like family of tyrosine kinase substrates: receptor-specific pattern of tyrosine phosphorylation and relationship to malignant transformation

A method for the isolation of tyrosine kinases substrates was developed. The method takes advantage of immuno-affinity purification of an entire set of proteins phosphorylated by tyrosine kinases, followed by generation of antisera against the purified protein pool and immunological screening of bacterial expression libraries with these antisera. By applying this methodology to the study of the phosphorylation events triggered by activation of the epidermal growth factor receptors, we have isolated several cDNAs encoding novel putative tyrosine kinase substrates. One of these cDNAs encodes radixin, a protein belonging to the band 4.1 family of proteins and highly related to ezrin and moesin. We demonstrated that, despite a high degree of relatedness, these three proteins exhibit a distinct receptor-specific pattern of phosphorylation, raising the possibility that they might mediate receptor-specific cellular changes. In addition the generation of antibodies specific for either radixin, ezrin or moesin allowed us to show that a previously described tumor transplantation antigen is indeed ezrin, thus implicating this protein in the determination of the biological phenotype of certain tumors.

Surgical management of the post-phlebitic leg syndrome

Twenty-five patients (32 limbs) with severe retrograde ejection venous syndrome (post-phlebitic leg syndrome) were surgically treated from 1971 to 1986 using a "very complete fasciotomy" with or without other individualized procedures. Clinical data, venographic findings, operative choices, and outcome were analyzed retrospectively. The theoretic benefit of adopting this new and conceptually accurate diagnostic label and the principle of "no incompetent perforators, no ulcers" is discussed. The patients generally had been managed for 10 to 20 years with conservative neglect or operative inadequacy. With correct conceptual understanding, anatomic stratification, defined indications for surgery, and individualization of procedures, an excellent result has been obtained with a low rate of serious complications. The very complete fasciotomy should be suitable for general use in treating this difficult and controversial syndrome.

Identification and biochemical characterization of novel putative substrates for the epidermal growth factor receptor kinase

To gain insight into the mechanisms which control the mitogenic response to epidermal growth factor (EGF), we have partially purified and characterized several intracellular proteins which are phosphorylated on tyrosine residues following activation of the epidermal growth factor receptor (EGFR). Partial purification was achieved by immunoaffinity chromatography using immobilized anti-phosphotyrosine antibodies. Antisera generated against the partially purified proteins were used to identify at least five novel EGFR putative substrates, designated, on the basis of their apparent molecular weight, p97, p68, p61, p56, and p23. All of these proteins became specifically phosphorylated on tyrosine after EGF treatment of intact cells, as assessed by phosphoamino acid analysis, and none of them represented an EGFR degradation product. The phosphorylation of these proteins appeared to be relatively specific for the EGFR. In particular, an EGFR-related kinase, erbB-2 was much less efficient than EGFR at phosphorylating p97, p56, and p23 and incapable of phosphorylating p68. The identification of these novel EGFR putative substrates should lead to a better understanding of the mechanisms controlling the specificity of EGFR-mediated mitogenic signaling.

Regulation of annexin I in adipogenesis: cAMP-independent action of methylisobutylxanthine

The differentiation of 3T3-L1 fibroblasts to adipocytes can be accelerated by the addition of 1-methyl-3-isobutylxanthine (MIX), insulin, and dexamethasone to the culture medium. During differentiation, we have demonstrated that the level of both annexin I mRNA and protein decreases. The half-times for this reduction were 2 h and 10 h for annexin I mRNA and protein, respectively. Of the added agents in the differentiation medium, only MIX caused a decline in annexin I expression in 3T3-L1 fibroblasts. The MIX effect in fibroblasts was reversible and required de novo transcription but not protein synthesis. Although MIX could be replaced by high levels of theophylline, neither agonists of the beta-adrenergic receptor nor intracellular second messengers, cAMP and cGMP, were able to reduce annexin I. The potential role of annexin I in cellular differentiation is discussed.

Mouse lipocortin I gene structure and chromosomal assignment: gene duplication and the origins of a gene family

Using cDNA probes obtained from library screening and anchored polymerase chain reaction, we have isolated and characterized three overlapping mouse genomic clones that contain the mouse lipocortin I (Lipo I) structural gene. Restriction enzyme mapping, Southern blotting, and DNA sequencing were carried out on the cloned genomic DNA. Lipo I spans about 17 kb and is divided into 13 exons encoding a protein of 346 amino acid residues. The promoter region of the gene has a TATA box and a CCAAT box located upstream of the transcription initiation site at -31 and -76 bp, respectively. Analysis of the strain distribution pattern of Lipo 1 in BXD and AKXD collections of recombinant inbred strains establishes that Lipo I is located on chromosome 19 in close proximity to Ea-4. While no striking relationship exists between the exon/intron structure of the gene and the four repeated 70-amino-acid domains of the protein, three of the four 17-amino-acid repeats believed to be responsible for Ca2+/phospholipid binding are encoded by the last codon of one exon and the first 16 codons of the following exon. This pattern supports the gene duplication theory, and the similarity in gene structure between mouse Lipo I and Lipo II suggests they have a recent evolutionary ancestor.

Protein-synthesis-dependent induction of annexin I by glucocorticoid

We demonstrate that annexin I/lipocortin I (lipo I) gene expression is regulated by dexamethasone (DEX) in mouse 3T3-L1 fibroblasts and LA-4 lung epithelial cells. We have characterized this induction further in 3T3-L1 fibroblasts. At 24 h after addition of DEX, the levels of lipo I mRNA and protein increased 5-fold and 1.5-fold respectively. Time-course experiments revealed that the induction was delayed by 2-4 h after DEX addition. Half-maximal induction of both lipo I mRNA and protein was achieved with 10 nM-DEX. Both actinomycin D and cycloheximide blocked the DEX effect on lipo I mRNA expression. These results indicate that the induction of lipo I by DEX has a transcriptional component and requires protein synthesis de novo.

Clinical experience with pefloxacin in patients with urinary tract infections

A total of 27 patients, 21 of them females, with a median age of 56 were treated with pefloxacin for urinary tract infections. Some 74% of these infections were associated with upper tract symptoms, and Escherichia coli was the most common causative micro-organism (75% of cases). Fifteen patients had co-existent diseases with/without urological abnormalities. All strains of E coli were sensitive to pefloxacin; Actinobacter and one strain of Klebsiella and Streptococcus faecalis were resistant. Two patients who defaulted and one who had an initial negative bacterial culture were excluded from the analysis of the outcome. The overall bacteriological cure rate at four to eight weeks was 87.5% (21/24). The incidence of possible side-effects was high, occurring in 59% of the patients. Nausea, dizziness and vomiting were the most common. These were mild and did not require termination of treatment. Peripheral neuropathy, which disappeared four weeks after stopping pefloxacin, occurred in one patient.

Differentiation of BC3H1 and primary skeletal muscle cells and the activity of their endogenous insulin-degrading enzyme are inhibited by the same metalloendoprotease inhibitors

Upon reduction of serum in their media, mouse BC3H1 muscle cells withdraw from the cell cycle and begin to differentiate. In differentiating cells, the induction of muscle-specific genes is accompanied by a distinct morphological chance. However, differentiated BC3H1 cells do not fuse with each other; they remain mononucleated. Metalloendoprotease inhibitors selectively block the differentiation of BC3H1 cells while inhibitors of other protease types are ineffective. In these cells, the degradation of the internalized insulin is initiated by a 110 kDa, non-lysosomal protease known as the insulin-degrading enzyme. The same metalloendoprotease inhibitors that block BC3H1 differentiation also inhibit, with a similar specificity and potency, the in vitro and the in vivo degradation of insulin by the insulin-degrading enzyme. When the serum in the medium is reduced, the activity of the insulin-degrading enzyme in the cell cytoplasm increases rapidly. This increase precedes any detectable change in the differentiation state of these cells by about 12 hours. These results, together with very similar ones obtained with primary rat skeletal muscle cells, support our earlier proposal that the insulin-degrading enzyme is the metalloendoprotease involved in the initiation of the morphological and biochemical differentiation of muscle cells in culture.

Sparganosis of the spinal cord. Case report

Sparganosis of the spinal cord is a rare disease: only two cases have previously been described. A third case of spinal sparganosis is reported in which a sparganum was removed from the central canal of the patient's spinal cord. The clinical presentation and pathology are described. A brief review of the life cycle of the Spirometra is given and the possible mode of infestation is discussed.

Metalloendoprotease inhibitors which block the differentiation of L6 myoblasts inhibit insulin degradation by the endogenous insulin-degrading enzyme

The cultured myoblasts of the rat skeletal muscle cell line L6 proliferate till confluency and then fuse to form myotubes and express a number of muscle-specific proteins. We had shown that this differentiation process is blocked by specific metalloendoprotease inhibitors. We now demonstrate that metabolizing L6 myoblasts and their cell extracts degrade insulin to acid-soluble fragments by a non-lysosomal pathway. About 90% of the insulin-degrading activity residues in the cytoplasm and is due to a 110-kDa enzyme known as the insulin-degrading enzyme. The same metalloendoprotease inhibitors that block the differentiation of L6 myoblasts also inhibit insulin degradation by the metabolizing L6 cells, their cell extracts, and the insulin-degrading enzyme immunoprecipitated from the cytosolic extracts by a monoclonal antibody. These results suggest that the insulin-degrading enzyme is the metalloendoprotease whose activity is required for the initiation of the morphological and biochemical differentiation of L6 myoblasts.

Cryptococcal infection of the lumbar spine

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A double-blind controlled trial of norfloxacin versus cotrimoxazole in the treatment of urinary tract infections

A double-blind controlled trial of norfloxacin versus cotrimoxazole in the treatment of urinary tract infections was conducted. Eighty-eight patients were recruited but data from 80 patients were analysed. Norfloxacin cured 93 per cent of the infections while the cure rate achieved by cotrimoxazole was only 70 per cent (p = 0.03, Fisher's exact test). The difference was attributable to a higher incidence of resistance to cotrimoxazole among the bacterial isolates. Escheria coli was the commonest pathogen and together with klebsiella accounted for 78 per cent of all isolates. Fifteen per cent of E coli and 15 per cent of klebsiella isolates were resistant to cotrimoxazole while all were sensitive to norfloxacin. Side effects were minimal and consisted mainly of nausea and non-specific dizziness.

Further observations on the first documented outbreak of trichinosis in Hong Kong

The first documented report of human trichinosis in Hong Kong is described comprising an outbreak amongst 20 Gurkha soldiers following a barbecue. The cardinal clinical features were fever, myalgia and facial oedema and the most useful laboratory tests were eosinophilia and elevated levels of creatinine phosphokinase. Gastrointestinal symptoms were uncommon. Seven patients who developed electrocardiographic abnormalities are the subject of an ongoing study. Four patients had psychiatric manifestations. Splinter haemorrhages, hypocalcaemia and evidence of renal dysfunction were absent. The parasite was recovered from 13 of patients and the diagnosis confirmed serologically in all. The value of the enzyme-linked immunosorbent assay (ELISA) for IgM and IgE antibodies is emphasized in that it is 100% specific and sensitive. Thiabendazole alone was used in treatment and all patients recovered.

Observations on semen quality of dogs in the tropics

Semen was obtained from eight mongrels and 17 purebred dogs kept in a tropical climate. The mean spermatozoal output per ejaculate was 303.6 +/- 138.2 and 602.9 +/- 466.2 million, respectively. Values for individual progressive motility, live and abnormal spermatozoa were comparable with those obtained in temperate regions. The type and frequency of spermatozoal abnormalities are illustrated.

A one-year survey of campylobacter enteritis and other forms of bacterial diarrhoea in Hong Kong

The following enteropathogens were isolated from the faeces of 769 (10.2%) of 7,545 patients of whom 5,704 had diarrhoea or abdominal pain, attending a teaching hospital in Hong Kong during one year: salmonellae 458 (6.1%); Vibrio parahaemolyticus 125 (1.7%); campylobacters 108 (1.4%); shigellae 83 (1.1%); others 19 (0.3%). Further identification of the campylobacter isolates showed that 63 (58%) were Campylobacter jejuni biotype 1, 44 (41%) were C. coli and only one was C. jejuni biotype 2. Seventy-five (69%) of the 108 campylobacters were isolated from children under two years of age, mostly during the second year of life. Faecal specimens from 1,841 children under the age of two years without gastrointestinal symptoms yielded almost the same percentages of salmonellae, campylobacters and shigellae as children with diarrhoea. Salmonellae, shigellae and vibrios were isolated most often in the hot late summer months (August to October), but, contrary to the pattern in Europe and North America, both C. jejuni and C. coli were most prevalent in the coolest months of the year (January to March). The reasons for this "reversed' trend are unknown.

A survey of fractures in the dog and cat in Malaysia

A survey of 61 canine and 26 feline fractures diagnosed between January 1980 and June 1983 at a veterinary teaching hospital was conducted. More than 80 per cent of the fractures occurred in animals less than two years old. Male animals were more frequently involved. In the dog, the femur, tibia, pelvis, radius and ulna were most often affected while in the cat, the femur, mandible, pelvis and spine were more often involved. All the findings were consistent with other reports in the literature.

Successful treatment of neurocysticercosis with low-dose praziquantel

A patient with neurocysticercosis was successfully treated with praziquantel. The clinical improvement was paralleled by the resolution of cerebral lesions as revealed by computerized tomography. This case study demonstrates the success of praziquantel and the effectiveness of low-dose regime in treatment of neurocysticercosis.

Salmonella meningitis in infancy

Despite adequate treatment, mortality and morbidity were high among the 13 cases of Salmonella meningitis in this series. Chloramphenicol, being a bacteriostatic agent against Salmonella species, is not a suitable antibiotic for the treatment of Salmonella meningitis. Treatment for 4-6 weeks is recommended with use of an antibiotic capable of achieving an adequate bactericidal concentration in the cerebrospinal fluid such as moxalactam. Intraventricular antibiotic treatment should be considered if there is a delay in the eradication of the Salmonella organisms from the cerebrospinal fluid after starting treatment.

The first documented outbreak of trichinellosis in Hong Kong Chinese

An outbreak of trichinellosis occurred in a Chinese family after the ingestion of inadequately cooked pork. Diagnosis was established by the demonstration of antibodies against Trichinella spiralis larval antigen by crossed immunoelectrophoresis and enzyme-linked immunosorbent assays, and living larvae in muscle biopsy. The main presenting symptom of these patients was pyrexia. Typical clinical features of Trichinella infection such as periorbital edema and severe myalgia were either minimal or absent. A history of having eaten insufficiently cooked meat is thus extremely important for correct diagnosis. We believe that this is the first documented report of a Trichinella outbreak in Chinese living in Hong Kong.

Serotypes of Escherichia coli isolated from patients with recurrent pyogenic cholangitis

Strains of Escherichia coli were isolated from laparotomy specimens from Chinese patients with recurrent pyogenic cholangitis in Hong Kong. A large variety of serotypes were found. Several sites were sampled in each patient. While only one serotype was normally isolated from one site, different sites often yielded different serotypes in the same patient. Generally the 'O' types found did not correspond to those found in the faeces of the Hong Kong Chinese population.

The bacteriology of recurrent pyogenic cholangitis and associated diseases

Ninety-five patients with recurrent pyogenic cholangitis had a range of specimens taken at laparotomy for bacterial culture. Bacteria were isolated from 68% of cases. Escherichia coli was the predominant pathogen. Other aerobic and anaerobic intestinal bacteria were also isolated. Liver biopsy, bile and gallstones were the most rewarding specimens for culture. Infection was usually localized, but systemic infection occurred occasionally. The site of infection is probably in the liver parenchyma; however, the route by which intestinal bacteria invade the liver is not known. Sixty per cent of the cases of recurrent pyogenic cholangitis had gallstones and 20% were infected with Clonorchis sinensis.

Quality assurance in surgical practice through auditing

An efficient auditing method is presented which involves objective criteria-based numerical screening of medical process and treatment outcome by paramedical staff and detailed analysis of deviated cases by surgeons. If properly performed it requires the study of no more than 50 cases in a diagnostic category to provide sufficient information about the quality of care. Encouraging points as well as problems are communicated to the surgeons to induce the maintenance or improvement of the standard of care. Graphic documentation of case performance is possible, allowing surgeons to compare results with their colleagues. The general performance level of several consecutive studies can be compared at a glance. In addition, logical education programs to improve the medical process can be designed on the basis of the problems identified. As all the cases with an unacceptable outcome are traceable to inadequate medical process, improvement in this area will decrease outcome defects. With the use of auditing and the follow-up technique described, the quality of care in surgery may be assured.

Resistance to chloramphenicol and ampicillin Salmonella johannesburg in Hong Kong: observations over a five-year period 1973-1977

Salmonella johannesburg has been prevalent in Hong Kong since 1973 and most strains were resistant to a multiplicity of antibiotics. The susceptibility of S. johannesburg strains isolated in a 5-year period from 1973 to 1977 to eight antimicrobial drugs including ampicillin (A), streptomycin (S), tetracycline (T), chloramphenicol (C), Kanamycin (K), sulphadiazine (Su), trimethoprim (Tm) and gentamicin (G) was tested by the agar dilution method. The proportion of strains resistant to chloramphenicol and ampicillin increased steadily during the 5-year period while those resistant to tetracycline decreased dramatically. This change was associated with an alteration of predominant patterns of antibiotic resistance: strains with the resistance pattern A.S.T.C.K.Su predominated in years 1973, 1974 and 1975 while those with the resistance pattern A.S.C.K.Su predominated in years 1976 and 1977. Analysis of the resistance patterns of S. johannesburg strains isolated from the same cases showed that the resistance pattern A.S.C.K.Su was more stable, and changed less frequently to other patterns of resistance than strains with the resistance pattern A.S.T.C.K.Su. In donor salmonella strains with the A.S.T.C.K.Su resistance pattern, transmissible factors carrying resistance to A.S.T.C.K.Su in toto, to A.S.T.C.Su,A.T.C.K.Su and to A or T alone were demonstrated. In donor salmonella strains with the A.S.C.K.Su resistance pattern, transmissible factors carrying resistance to A.S.C.K.Su in toto and to A.S.K.Su were detected. The significance of the carriage of such transmissible resistance factors by this Salmonella is briefly discussed.

Serotypes of Escherichia coli from urinary tract infections in Hong Kong

Strains of E. coli, mainly from Chinese patients in Hong Kong with urinary tract infections, were serotyped, biotyped, and their antibiotic resistance patterns determined. The most common O groups found were O1, O2, O4, O6, O7, O8, O21, O25 AND O82. In general, they carried flagellar antigens different from those normally associated with these O groups in Europe. A variety of biotypes was observed and many strains were resistant to a number of antimicrobial drugs.

Medical students in community physicians' offices

Can the medical student benefit from spending time in the offices of community physicians? Eight consecutive final-year medical students visited the offices of 39 physicians, 31 family physicians and eight specialists, in the communities of Richmond and Delta, British Columbia. The students describe the value of their experience, common problems seen, continuity of care, practice variation, opportunities in specialist office practice and the standard of practice observed. We strongly suggest that some medical student instruction must take place in the community to ensure improved patient care from doctors with a reality-based training. All students, whatever their eventual area of work, would benefit from this experience and we recommend that other centres try similar experiments.

Six medical students in a community hospital

This paper describes part of an education experiment at the University of British Columbia at Vancouver.Six final-year medical students spent approximately 12 weeks in a community. Their time was divided between the hospital and various doctors' offices. They answered a simple questionnaire to describe their experiences and commented favourably upon the opportunities for direct patient contact, learning basic skills, informal teaching by both family physicians and consultants, and the variety of work available.They had the opportunity to follow up the progress of the patient and learn the natural history of common illnesses. They achieved their basic objectives. We conclude from their reports and informal conversation that the experiment was successful and recommend other institutions to try similar programs.

The function of the basal filaments in the parietal layer of Bowman's capsule

A number of cell types in the nephron have been known for some time to contain basally located filaments demonstrable by a variety of both light and electron microscopic techniques.]t has been proposed that these filaments may provide a contractile mechanism which would have implications for the control of renal function. One site in which these filaments have been observed is in the parietal layer of Bowman's capsule. The present study was designed to see if contraction of this layer of cells could be demonstrated and if so whether the basal filaments appeared to play a role in the process. Renal cortical tissue was fixed both in vivo and in vitro in the presence and absence of histamine, adrenaline, and acetylcholine and examined by conventional electron microscopic techniques. Basal folding of the cell membrane was observed particularly in the adrenaline-treated tissue and was interpreted as reflecting a conformational change in the cell such as might be expected with contraction. The relationship of this folding, however, to the arrangement of the basal filaments was such as to suggest that contraction of the filaments was not responsible for the folding observed. Alternative roles for the fibrils either as a structural framework or as a component in an attachment mechanism of the cells to the underlying basement membrane were therefore proposed.

Colicine types of Shigella sonnei isolated in Hong Kong

Two-hundred and twenty-five strains of Shigella sonnei isolated from sporadic cases of bacillary dysentery were subjected to colicine typing. The result showed that types 15 and 12 were the prevailing types in Hong Kong and two new types which did not fit in with the colicine patterns of the current types were observed. A marked increase in the numbers of strains concurrently resistant to chloramphenicol, tetracycline, and streptomycin occurred in recent years. However, there was no correlation between drug resistance or biochemical pattern and colicine types. Consistency of colicinogenicity was confirmed by the fact that even a rough variant of a smooth strain had not changed its colicine pattern.