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Biomedical subjects

L Alterman

Publications and source records attributed to L Alterman.

10 recordsLinked to original sources
PubMed1997

B-cell-negative severe combined immunodeficiency associated with a common gamma chain mutation.

Severe combined immunodeficiency (SCID) is caused by a variety of underlying defects. Approximately 40% of cases are thought to be of the X-linked type (SCIDX1), which is phenotypically characterised by the absence, or very low numbers, of T cells, but normal or even high B cell numbers. The gene responsible for SCIDX1 is that coding for the common gamma chain (gamma c), a component of multiple cytokine receptors. Mutations in this gene have been demonstrated in a large number of boys affected by typical SCIDX1. We describe a sporadic case of a boy who had SCID with absent B cells and absent T cells, but in whom a mutation in the gamma c gene has been demonstrated. In the absence of a typical X-linked pedigree, the phenotype in this boy suggested an autosomal recessive form of SCID and the family would usually have been counselled accordingly. This family raises the question of the true frequency of SCIDX1 amongst sporadic male cases of SCID and highlights the need to screen these boys for gamma chain mutations.

Antigens, CD↗
PubMed1996

X linked agammaglobulinaemia with a 'leaky' phenotype.

Typical X linked agammaglobulinaemia (XLA) is characterised by absence of immunoglobulin production and lack of mature B cells. The gene responsible for XLA has recently been identified, and codes for a B cell tyrosine kinase, BTK. A family affected by a B cell immunodeficiency, which is less severe than classical XLA, is described but they had a pedigree suggestive of X linked inheritance. Demonstration of a mutation in the BTK gene confirms that this is a mild form of XLA.

Agammaglobulinemia↗
PubMed1989

Allergenic and antigenic relationship between three species of storage mite and the house dust mite, Dermatophagoides pteronyssinus.

We have explored the antigenic and allergenic relationship between the house dust mite Dermatophagoides pteronyssinus and three species of storage mite, Glycyphagus destructor, Acarus siro, and Tyrophagus longior. Crossed immunoelectrophoresis demonstrated that all the mite extracts contained multiple antigens but that there was only limited cross-reactivity between the different species. Six sera were obtained from workers exposed to storage mites and with occupationally related lower respiratory tract symptoms. All workers had specific IgE to D. pteronyssinus and to one or more of the storage mites. The pattern of reactivity varied between the different sera, two responded primarily to D. pteronyssinus and A. siro and four sera to D. pteronyssinus and G. destructor. Only weak responses were observed to T. longior. RAST-inhibition and affinity-absorption experiments demonstrated that D. pteronyssinus had at least three groups of distinct allergenic determinants, determinants specific to D. pteronyssinus, determinants shared with A. siro, and determinants shared with G. destructor. Similarly, both A. siro and G. destructor have specific allergenic determinants and determinants shared with D. pteronyssinus. The findings demonstrate the complexity of the immunologic responses to the different mite species.

Allergens↗
PubMed1989

The allergens of dog. I. Identification using crossed radio-immunoelectrophoresis.

The antigens present in an extract of dog hair and dander were examined by crossed immunoelectrophoresis (CIE) and the IgE-binding allergens by crossed radio-immunoelectrophoresis (CRIE), respectively, using sera from 60 British and Finnish animal-allergic subjects. The extract was comprised of a minimum of 28 antigens, 11 of which were common to dog serum. IgE antibody in the sera of the dog-sensitive patients bound to 21 of the 28 antigens at varying frequencies and intensities. Binding of any intensity occurred most frequently to two serum proteins: antigen 23 (IgG) binding IgE in 88% of cases, and antigen 3 (dog serum albumin, DSA) in 77% of cases. Dander antigen 8 bound in 63% and antigen 1 in 42% of the sera. Strong IgE binding, however, was most commonly associated with dander antigen 8 followed by antigens 1 and 23 (IgG) then 3 (DSA). The ranking of the antigens as allergens was similar for the two populations except that DSA was more important for the British than for the Finnish subjects.

Allergens↗
PubMed1987

The use of monoclonal antibodies raised against a human IgE myeloma paraprotein for the study of allergen extracts and sera from allergic patients.

Murine monoclonal antibodies have been produced against a single human IgE myeloma preparation. A single fusion yielded six different monoclonal antibodies which bound strongly to the immunogen. Two of these failed to react with 'normal' human IgE or with a second IgE paraprotein. The other four antibodies reacted with normal and myeloma-derived IgE and were found to be specific for antibodies of this class. Two of these antibodies were potent reagents for the detection of IgE by two site immunoradiometric assay, immunoblotting, and radioallergosorbent test. The other two antibodies were considerably less potent reagents when used in these assay systems. Our findings suggest that care should be taken in selection of suitable monoclonal antibodies for immunochemical study of allergens and sera from allergic patients.

Allergens↗
PubMed1984

Comparison of long-term renal hemodynamic effects of methyldopa and propranolol in patients with hypertension and renal insufficiency.

Studies were carried out in 15 patients with renal insufficiency and hypertension to compare the long-term effects of methyldopa and propranolol on renal hemodynamics. Inulin and PAH clearance measurements were made under baseline conditions and four to six months of antihypertensive therapy with each of the two drugs. Eight of the 15 patients (group I) were started on methyldopa and then switched to propranolol; and in the other seven (group II), the sequence was reversed. There were no statistical differences in blood pressure or inulin or PAH clearances under baseline conditions between the two groups of patients. Blood pressure was controlled equally with the two drugs in combination with furosemide. In group I, there was no significant effect of either antihypertensive drug on inulin clearance, but PAH clearance was significantly higher during methyldopa than propranolol therapy. In group II, the same higher PAH clearance was found with methyldopa, even though the sequence of drug administration was opposite to that of group I. Challenge with iv furosemide resulted in a greater 3-hour natriuresis during methyldopa than propranolol treatment. The observations indicate that glomerular filtration rate (GFR) is not significantly affected by long-term treatment with methyldopa or propranolol but that renal plasma flow (RPF) is higher during treatment with methyldopa in patients with renal insufficiency and hypertension. The higher RPF apparently enhances the acute natriuretic effect of iv furosemide.

Adult↗
PubMed1983

Selective deep nephron hyperfiltration in uninephrectomized spontaneously hypertensive rats.

Studies were carried out to determine the effect of uninephrectomy (UNX) on single nephron hemodynamics and proteinuria in the spontaneously hypertensive rat (SHR). Four groups were studied: two-kidney SHR and normotensive WKY controls; SHR + UNX and WKY + UNX. UNX was performed at age 8 to 10 weeks. Blood pressure and protein excretion were measured periodically, and micropuncture experiments of cortical nephrons were carried out at age 32 to 40 weeks. Systolic blood pressure was not significantly different between SHR and SHR + UNX. Protein excretion increased markedly in the SHR + UNX 6 months after UNX, as compared with the other three groups. In cortical nephrons, single nephron glomerular filtration rate (SNGFR) and plasma flow entering the glomeruli (SNPF) was lower in SHR + UNX than in WKY + UNX. Glomerular hydraulic pressure (PG) during stopped flow was closely comparable in all groups, rising only 2 mm Hg after UNX. SNGFR was measured in juxtamedullary (JM) nephrons 2 months after UNX, a stage before heavy proteinuria developed. We found that JM SNGFR was approximately 50% higher in SHR + UNX than in WKY + UNX. The observations suggest that following ablation of renal mass, superficial cortical glomeruli are not exposed to excessively high pressure or flow rates in the SHR. In contrast, JM glomeruli undergo a disproportionate rise in SNGFR, presumably associated with excessively high PG and/or blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1980

Synthesis and insertion of cytochrome P-450 into endoplasmic reticulum membranes.

Treatment of rats with phenobarbital leads to a substantial increase in levels of translatable liver cytochrome P-450 mRNA. This mRNA is primarily associated with ribosomes bound to endoplasmic reticulum membranes which in an in vitro system synthesized approximately 10 times more cytochrome P-450 than did free polysomes from the same animals. Cytochrome P-450 synthesized by rough microsomes in vitro appears to be directly inserted into the membranes because it was not released by a treatment with low detergent concentrations that released albumin and other microsomal content proteins. The amino-terminal amino acid sequence of cytochrome P-450 synthesized in an mRNA-dependent system resembles in hydrophobicity the signal segment of presecretory proteins and therefore may serve to insert the polypeptide into the membrane during synthesis. In contrast to the situation with secretory proteins and several other membrane proteins, however, the putative insertion signal of cytochrome P-450 is not removed by a membrane-associated peptidase and remains in the mature polypeptide.

Animals↗