Delta 4-3-oxosteroid 5 beta-reductase deficiency: failure of ursodeoxycholic acid treatment and response to chenodeoxycholic acid plus cholic acid

BACKGROUND

In some infants with liver disease, 3-oxo-delta 4 bile acids are the major bile acids in urine, a phenomenon attributed to reduced activity of the delta 4-3-oxosteroid 5 beta-reductase required for synthesis of chenodeoxycholic acid and cholic acid. These patients form a heterogeneous group. Many have a known cause of hepatic dysfunction and plasma concentrations of chenodeoxycholic acid and cholic acid that are actually greater than those of the 3-oxo-delta 4 bile acids. It is unlikely that these patients have a primary genetic deficiency of the 5 beta-reductase enzyme.

AIMS

To document the bile acid profile, clinical phenotype, and response to treatment of an infant with cholestasis, increased plasma concentrations of 3-oxo-delta 4 bile acids, low plasma concentrations of chenodeoxycholic acid and cholic acid, and no other identifiable cause of liver disease.

PATIENTS

This infant was compared with normal infants and infants with cholestasis of known cause.

METHODS

Analysis of bile acids by liquid secondary ionisation mass spectrometry and gas chromatography-mass spectrometry.

RESULTS

The plasma bile acid profile of the patient was unique. She had chronic cholestatic liver disease associated with malabsorption of vitamins D and E and a normal gamma-glutamyltranspeptidase when the transaminases were increased. The liver disease failed to improve with ursodeoxycholic acid but responded to a combination of chenodeoxycholic acid and cholic acid.

CONCLUSION

Treatment of primary 5 beta-reductase deficiency requires the use of bile acids that inhibit cholesterol 7 alpha-hydroxylase.

Ataxia associated with increased plasma concentrations of pristanic acid, phytanic acid and C27 bile acids but normal fibroblast branched-chain fatty acid oxidation

Investigations of peroxisomal function were undertaken in an 8-year-old girl who developed motor difficulties at the age of 3.5 years and went on to develop a progressive ataxia and dysarthria. There were no other neurological abnormalities and she was of normal intelligence. Analysis of plasma very long-chain fatty acids revealed a normal C26 concentration and normal C24/C22 and C26/C22 ratios. Analysis of branched-chain fatty acids showed an elevated plasma phytanic acid concentration of 60 mumol/L (normal < 15) and a considerably elevated pristanic acid concentration of 50 mumol/L (normal < 2). Plasma concentrations of the C27 bile acids 3 alpha, 7 alpha-dihydroxycholestanoic acid (DHCA) and 3 alpha, 7 alpha, 12 alpha-trihydroxycholestanoic acid (THCA) and of the C29-dicarboxylic acid were also increased. We postulated that these results might be due to deficiency of the peroxisomal branched-chain acyl-CoA oxidase, but when oxidation of branched-chain fatty acids was studied in cultured skin fibroblasts it was found to be normal. Alternative explanations for the accumulation of branched-chain substrates for peroxisomal beta-oxidation are discussed. Treatment with a low-phytanic acid diet arrested the progression of the ataxia and led to a slight improvement.

Prenatal diagnosis of Smith-Lemli-Opitz syndrome

An abnormality in cholesterol synthesis was described recently in the Smith-Lemli-Opitz (SLO) syndrome. Here we describe how the application of this finding has enabled an accurate prenatal diagnosis. We also discuss the possible use of this test in detecting heterozygotes.

Mechanisms of free radical oxidation of unsaturated lipids

The primary products formed from the autoxidation of lipids can be understood based upon a mechanism that involves five different reaction types. These reactions are: reaction of a carbon radical and molecular oxygen, atom transfer of a hydrogen from substrate to the chain carrying peroxyl, fragmentation of the chain carrying peroxyl to give oxygen and a carbon radical, rearrangement of the peroxyl, and cyclization of the peroxyl. The mechanism of these primary reaction steps has been the focus of extensive research over the past fifty years, and the current level of understanding of these transformations is the subject of this review.

Genetic mapping near the myd locus on mouse chromosome 8

Myodystrophy (myd), an autosomal recessive mutation of the mouse characterized by progressive weakness and dystrophic muscle histology, maps to the central portion of Chromosome (Chr) 8 (Lane et al. J. Hered 67, 135, 1976). This portion of Chr 8 contains the genes for a mitochondrial uncoupling protein (Ucp) and kallikrein (Kal3), which map to distal 4q in the human, providing evidence for a segment of homology. Characteristics of the myd phenotype coupled with this homology suggest that myd may be a mouse homolog of facioscapulohumeral muscular dystrophy (FSHD), which maps to human 4q35. We have confirmed and expanded the region of mouse 8-human 4 homology by generating a map of Chr 8 in an interspecific backcross of C57BL/6J and a partially inbred strain derived from M. spretus. The map is comprised of the genes for Ucp, coagulation factor XI (Cfl1), and chloride channel 5 (Clc5), all of which have homologs on distal human 4q, 15 microsatellite loci, and the membrane cofactor protein pseudogene (Mcp-ps). To place myd in the genetic map, 75 affected progeny from an intersubspecific backcross of animals heterozygous for myd with Mus musculus castaneus were genotyped with Chr 8 microsatellite loci. The mutation maps between D8Mit30 and D8Mit75, an interval that is flanked by genes with human homologs at distal 4q. These results are consistent with the possibility that myd is the mouse homolog of FSHD.

Mouse myodystrophy (myd) mutation: refined mapping in an interval flanked by homology with distal human 4q

Myodystrophy (myd) is an autosomal-recessive mouse mutation with dystrophic skeletal muscle. We propose that myd may be a model of the human disorder facioscapulohumeral dystrophy (FSHD) on the basis of clinical features and homologous genetic map locations. FSHD maps to human 4q35, while myd maps to mouse chromosome 8. To explore the relationship between FSHD and myd, it is necessary to define the homologous regions of human chromosome 4 and mouse chromosome 8, and ultimately, identify the genes underlying both disorders. A kallikrein gene (KaL3) was previously mapped by in situ hybridization to mouse chromosome 8 and human 4q35. We report the genetic map location of Kal3, bringing to 4 the number of genes with homologues on human 4q31-35 placed on the genetic map of mouse chromosome 8. As a first step in gene isolation, we have narrowed the interval containing myd by typing 125 affected mice with microsatellite markers. Analysis of recombinants placed myd in an interval that is flanked by genes with homologues in human 4q.

Orbital lymphoma associated with acquired immune deficiency syndrome (AIDS)

A new case of AIDS-associated, small noncleaved cell (Burkitt's) lymphoma that presented as an orbital mass is described. Extraocular muscle involvement was documented by computed tomography and confirmed by orbital biopsy. Extensive abdominal involvement was subsequently diagnosed and this caused the patient's death only 15 days after the initial consultation and orbital biopsy. A literature review discloses only eight previous case reports of AIDS-associated non-Hodgkin's lymphoma (NHL) involving the orbit: two cases of Burkitt's type and six cases of large cell immunoblastic type. Three additional cases of orbital NHL can be found among larger series of AIDS cases. Affected patients are uniformly young adult males with a history of homosexuality and/or IV drug abuse. Variations in clinical presentation are discussed. Although the morphology of the histopathologic specimen in our case was consistent with a high-grade, small noncleaved cell NHL, flow cytometry revealed an atypical immunophenotype for Burkitt's lymphoma in that CD20 and immunoglobulin light chain antigens were not expressed. Morphologic classification and immunophenotypic characteristics of AIDS-associated NHLs are discussed.

Phytosterolemia in children with parenteral nutrition-associated cholestatic liver disease

BACKGROUND

Lipid emulsions used for parenteral nutrition (PN) contain phytosterols. Our hypothesis was that these phytosterols can accumulate and contribute to cholestatic liver disease and other complications of PN, e.g., thrombocytopenia (which occurs in hereditary phytosterolemia).

METHODS

Using gas chromatography-mass spectrometry, plasma concentrations of sterols were measured in 29 children aged 2 months to 9 years receiving PN and in 29 age-matched controls. The children receiving PN fell into two subgroups: 5 with severe PN-associated cholestatic liver disease (bilirubin level, > 100 mumol/L; aspartate aminotransferase [AST] level, > 200 U/L) and 24 with a bilirubin level of < 100 mumol/L and/or AST level of < 200 U/L.

RESULTS

The 5 children with severe PN-associated liver disease had plasma concentrations of phytosterols and sitostanol that were as high as those seen in patients with hereditary phytosterolemia (total phytosterols 1.3-1.8 mmol/L). All 5 had intermittent thrombocytopenia. A reduction in intake of lipid emulsion to < 50 mL.kg-1.wk-1 was associated with a decrease in plasma phytosterol concentrations and an improvement in liver function tests and platelet counts in two patients. Children with less severe PN-associated liver disease had lower plasma phytosterol concentrations than the 5 with severe disease.

CONCLUSIONS

Children receiving PN who have high plasma phytosterol concentrations also have cholestatic liver disease and thrombocytopenia; phytosterolemia might contribute to the pathogenesis of complications of PN.

Capsular tissue: a new local flap

Capsular tissue, the interface that forms between an implanted device and the body's own soft tissues, has recently been shown to develop its own unique blood supply. This capsular tissue with its extensive vascular plexus has not been described previously as an isolated flap. The purpose of our study was to determine whether an isolated flap of capsular tissue would survive as a local pedicle flap and provide enough inherent vascularity to support a skin graft. Isolated expanded and nonexpanded capsular flaps were compared by using 20 expanders (10 expanded and 10 nonexpanded) in two mixed-breed female pigs. Expanded and nonexpanded capsular flaps were elevated 8 weeks following expander placement. These flaps were raised on their capsular bases alone, and skin grafts were placed onto the capsular surfaces. All the expanded capsular flaps and their skin grafts had 100 percent survival. Skin grafts on the nonexpanded flaps survived an average of 28 percent, with graft survival corresponding to flap survival. This study confirms that flaps of isolated expanded capsular tissue survive and provide enough inherent vascularity to support a split-thickness skin graft.

General practitioner records on computer--handle with care

This 1 year prospective study involved nine general practitioners in an urban health centre who routinely record all patient contacts on computer. The study determines by comparison with a manual record how accurately doctors record laboratory investigations on computer and compares the effectiveness of three interventions in improving the completeness of computerized recording of presenting symptoms, problems/diagnoses and laboratory investigations. Recording was analysed for 1 month prior to and for two 1 month periods following each intervention. A control group was used. A total of 7983 patient contacts were analysed. Intervention led to an improvement in the recording of presenting symptoms and problems/diagnoses. Recording of investigations on the computer showed no improvement, remaining at one-third of the total in the treatment room book for both study and control doctors. The effectiveness of the different forms of intervention depended on both the aspect of the consultation considered and the familiarity of individual doctors with the method of data collection. Aspects considered less important required greater intervention to bring about a marked improvement, as did doctors relatively new to the practice. It may not be possible to get all aspects of the consultation recorded with the same degree of accuracy. This has implications for the accuracy of retrospective studies dependent on existing computerized data.

Genetic and physical maps of human chromosome 4 based on dinucleotide repeats

Characterization of inherited variations within tandem arrays of dinucleotide repeats has substantially advanced the construction of genetic maps using linkage approaches over the last several years. Using a backbone of 10 newly identified microsatellite repeats on human chromosome 4 and 6 previously identified short tandem repeat element polymorphisms, we have constructed several genetic maps and a physical map of human chromosome 4. The genetic and physical maps are in complete concordance with each other. The genetic maps include a 15-locus microsatellite-based linkage map, a framework map of high support incorporating a total of 39 independent loci, a 25-locus high-heterozygosity, easily used index map, and a gene-based comprehensive map that provides the best genetic location for 35 genes mapped to chromosome 4. The 16 microsatellite markers are each localized to one of nine regions of chromosome 4, delineated by a panel of somatic cell hybrids. These results demonstrate the utility of PCR-based repeat elements for the construction of genetic maps and provide a valuable resource for continued high-resolution mapping of chromosome 4 and of genetic disorders to this chromosome.

Characterization of the human HOX 7 cDNA and identification of polymorphic markers

cDNA clones for a human HOX 7 gene obtained with homologous clones of Drosophila were used in human gene mapping studies. The human cDNA clone was isolated from a library constructed from human embryonic craniofacial material. The sequence of the cDNA demonstrates significant homology with mouse HOX 7. A search for RFLPs identified MboII and BstEII variants. A CA dinucleotide repeat with 5 alleles was also identified and allowed placement of HOX 7 into a defined linkage map. Evidence for linkage disequilibrium was found with markers tested. These results place the human HOX 7 gene in a defined position on 4p.

Genetic and physical mapping on chromosome 4 narrows the localization of the gene for facioscapulohumeral muscular dystrophy (FSHD)

We have used a combination of classical RFLPs and PCR-based polymorphisms including CA repeats and single-strand conformation polymorphisms to generate a fine-structure genetic map of the distal long arm of chromosome 4q. This map is now genetically linked to the pre-existing anchor map of 4pter-4q31 and generates, for the first time, a complete linkage map of this chromosome. The map consists of 32 anchor loci placed with odds of greater than 1,000:1. The high-resolution map in the cytogenetic region surrounding 4q35 provides the order 4cen-D4S171-F11-D4S187-D4S163-D4S139-4q ter. When we used somatic cell hybrids from a t(X;4)(p21;q35) translocation, these five markers fell into three groups consistent with the genetic map-D4S171 and F11 in 4pter-4q35, D4S163 and D4S139 in 4q35-4qter, and D4S187 as a junction fragment between these two regions. These markers are in tight linkage to the gene for facioscapulo-humeral muscular dystrophy (FSHD) mapped to this region by several collaborating investigators and provide a framework for further detailed analysis of this region.

Linkage localization of facioscapulohumeral muscular dystrophy (FSHD) in 4q35

Fasioscapulohumeral muscular dystrophy (FSHD) has recently been localized to 4q35. We have studied four families with FSHD. Linkage to the 4q35 probes D4S163, D4S139, and D4S171 was confirmed. We found no recombinants helpful in detailed localization of the FSHD gene. Two of our families include males with a rapidly progressive muscle disease that had been diagnosed, on the basis of clinical features, as Duchenne muscular dystrophy. One of these males is available for linkage study and shares the haplotype of his FSHD-affected aunt and cousin.

Construction of a human chromosome 4 YAC pool and analysis of artificial chromosome stability

In order to construct a human chromosome 4-specific YAC library, we have utilized pYAC4 and a mouse/human hybrid cell line HA(4)A in which the only human chromosome present is chromosome 4. From this cell line, approximately 8Mb of chromosome 4 have been cloned. The library includes 65 human-specific clones that range in size from 30kb to 290kb, the average size being 108kb. In order to optimize the manipulation of YAC libraries, we have begun to investigate the stability of YACs containing human DNA in yeast cells; these studies will also determine if there are intrinsic differences in the properties of chromosomes containing higher eukaryotic DNAs. We are examining two kinds of stability: 1] mitotic stability, the ability of the YAC to replicate and segregate properly during mitosis, and 2] structural stability, the tendency of the YAC to rearrange. We have found that the majority of YACs examined are one to two orders of magnitude less stable than authentic yeast chromosomes. Interestingly, the largest YAC analyzed displayed a loss rate typical for natural yeast chromosomes. Our results also suggest that increasing the length of an artificial chromosome improves its mitotic stability. One YAC that showed a very high frequency of rearrangement by mitotic recombination proved to be a mouse/human chimera. In contrast to studies using total human DNA, the frequency of chimeras (i.e., mouse/human) in the YAC pool appeared to be low.

Diabetes care by general practitioners in Northern Ireland: present state and future trends

A questionnaire returned by 250 (71.4%) of the 350 general practices in Northern Ireland indicated that although only 34 practices had special arrangements for seeing their diabetic patients, 178 practices stated that they would like to be more involved in the care of their non-insulin-dependent diabetes mellitus (NIDDM) patients. One hundred and eight practices felt the same way about their insulin-dependent diabetes mellitus (IDDM) patients. One hundred practices stated that the partners felt competent to manage their diabetic patients. The main area where general practitioners felt they needed to improve their knowledge was ophthalmology (56 practices). When asked which type of care scheme would appeal most to their practice, 135 practices stated that regular attendance with the general practitioner and annual hospital review would be the preferred arrangement. Overall there was a positive attitude towards increased general practitioner involvement in diabetes care.

Pleural effusion with rheumatoid arthritis

Pleural effusions complicating rheumatoid arthritis occur most commonly in middle-aged men. The majority of these individuals will be symptomatic with pleuritic chest pain and/or dyspnea. Rheumatoid pleural effusions have distinct chemical characteristics including elevated LDH, low glucose and low pH. The finding of a rheumatoid nodule on pleural biopsy, is pathognomonic of a rheumatoid associated pleural effusion. Treatment of this spectrum of the disease is aimed at preventing progressive pleural fibrosis.

Parathyroid cyst: case report of a rare surgical lesion of the neck

A thirty-two year old female presented with a neck mass of probable thyroid origin. Repeated fine needle aspirations failed to provide diagnostic tissue or long-term resolution of the cystic mass. The clinical and pathologic findings in this case of a parathyroid cyst are presented. Parathyroid cyst is a rare cause of neck mass. Recurrence of a cyst is also unusual following aspiration. The aspiration of clear watery fluid from a neck mass offers presumptive evidence of a parathyroid cyst. The demonstration of parathyroid hormone in the cyst fluid is considered diagnostic.

Patients on H2-receptor antagonists--are we investigating them?

A survey was made of patients receiving H2-receptor antagonists in a group practice serving 8600 patients. Two hundred and twelve patients (2%) who had received at least one prescription for H2 antagonists in a 12 month period were identified. When compared with the practice population, men and patients over 50 years old were more likely to be taking these drugs (P less than 0.01 and P less than 0.001, respectively). One hundred and fifty-seven patients (74%) were investigated before commencing therapy; 114 (73%) of these patients were investigated via the hospital outpatient department, despite the general practitioners having full open access to barium meals. Only 23 (15%) of the patients investigated were found to have no active pathology. Twenty-nine (14%) of the 212 study patients had received one or more gastrointestinal investigations in the 18 months subsequent to starting H2-antagonist therapy. Twenty-five of these patients had also received an investigation before starting therapy. One hundred and eleven patients (52%) had had their H2 antagonist therapy initiated by their general practitioner.

A computerized audit of non-steroidal anti-inflammatory drug prescribing in general practice

The two group practices based in a city health centre decided to prescribe non-steroidal anti-inflammatory drugs in generic form from an agreed date. The practices' computer was used to identify the number of repeat prescriptions being issued for this group of drugs and to monitor the effectiveness of the changeover. Although both practices showed a marked increase in the level of generic prescribing there was considerable interpractice variation. Generic prescribing for one practice increased from 4% to 64% and for the other from 1% to 38% of repeat prescriptions issued for non-steroidal anti-inflammatory drugs over the study period. The reasons for this variation, the advantages of computerized audit and the problems associated with this self-imposed audit are discussed.

Repeat prescribing of non-steroidal anti-inflammatory drugs excluding aspirin: how careful are we?

About 5% of all National Health Service prescriptions in Britain and a quarter of reports of suspected adverse reactions are accounted for by non-steroidal anti-inflammatory drugs. Their prescription was investigated in two computerised group practices serving 11850 patients. Altogether 198 patients receiving repeat prescriptions of non-steroidal anti-inflammatory drugs were identified and relevant clinical details extracted from their notes. Of these patients, 119 were over 65 years old; 172 were receiving one of six different non-steroidal anti-inflammatory drugs; and 76 were taking drugs that can interact with non-steroidal anti-inflammatory drugs. Ninety one patients had one or more medical conditions that may be aggravated by non-steroidal anti-inflammatory drugs, and 36 had experienced side effects important enough for their treatment to be changed. A questionnaire to assess opinions and knowledge of non-steroidal anti-inflammatory drugs was given to 42 general practitioners and 26 rheumatologists. Although the two groups showed a comparable knowledge of the properties and costs of non-steroidal anti-inflammatory drugs, they differed significantly in their views on the circumstances under which these drugs should be used. Clear guidelines on the prescription of these drugs would indicate when careful monitoring is essential for patients to benefit from them safely.

Effect on prescribing of the limited list in a computerised group practice

The prescribing of drugs in the therapeutic classes that are affected by the government's limited list was investigated in a computerised group practice of just over 3,000 patients. Prescribable drugs in categories that are affected by the list were identified for two consecutive six month periods before and one six month period after the introduction of the list. A significant decrease in the prescribing of cough and cold remedies, vitamins, and antacids occurred after the list was introduced, whereas no change occurred in the prescribing of laxatives, benzodiazepines, or analgesics. The prescribing of iron and penicillin increased significantly after the list was introduced, whereas the use of H2 antagonists and non-steroidal anti-inflammatory drugs showed no significant change.

General practitioner workload with 2,000 patients

This study was designed to investigate the relationship between general practice workload, the number of partners in the practice, and the use of health centre premises. Thirty general practitioners in twelve randomly selected practices (each with a list size of 2,000 patients per doctor) agreed to record a week's work on pre-printed forms. Information was gathered on content of care in the surgery, number of non-surgery and indirect contacts and time spent on work activities. Content of care was influenced by whether or not the doctors were based in a health centre, rather on how many partners they had. Conversely the numbers of non-surgery and indirect contacts and the time spent on all work activities were more affected by the number of partners. Two factors - consultation rate and the rate at which doctors initiate consultations - were found to be independent of either of the two variables considered.