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Biomedical subjects

R P Sarkany

Publications and source records attributed to R P Sarkany.

13 recordsLinked to original sources
PubMed2001

The management of porphyria cutanea tarda.

Porphyria cutanea tarda (PCT), the commonest of all porphyrias, is usually characterized by blisters and fragility of skin in light-exposed areas. It can be clinically indistinguishable from other disorders including variegate porphyria and the diagnosis can only be made by rigorous biochemical analysis. PCT does not cause acute attacks of porphyria. It is usually an acquired condition caused by inhibition of the uroporphyrinogen decarboxylase enzyme in the liver. Hereditary haemochromatosis, hepatitis C virus infection, alcohol, oestrogens and a family history of PCT are the major risk factors for the condition and should be searched for specifically in all patients. Liver disease, including hepatocellular carcinoma, is common in patients with PCT, and should be investigated for at presentation by means of a liver biopsy where possible. Patients with severe hepatic pathology or longstanding untreated PCT need to be monitored for the development of hepatocellular carcinoma in the long term. Low dose twice weekly chloroquine is the mainstay of treatment, but venesection should be used in patients with severe iron overload or hepatitis C-related liver disease. Subsequently, long-term follow-up is needed in all patients to monitor for relapse.

Humans↗
PubMed1999

Home phototherapy: report on a workshop of the British Photodermatology Group, December 1996.

Phototherapy is a popular and effective treatment for many patients with skin diseases. However, repeated journeys to hospital for phototherapy can be inconvenient and expensive. If it were available, many patients might prefer home-based phototherapy as long as it was safe and effective. Indeed, many psoriasis patients already self-treat with ultraviolet A sunbeds at home. This report represents a consensus view from a British Photodermatology Group workshop held in December 1996, the purpose of which was to examine the potential role of home-based phototherapy in dermatological practice. We conclude that home-based therapy represents a suboptimal treatment with greater attendant risks than phototherapy in a hospital environment. The level of medical supervision of the home treatment is crucial to its safety and effectiveness. Until further studies are forthcoming, home phototherapy should be largely restricted to those with overwhelming difficulties in attending hospital.

Home Care Services↗
PubMed1999

Porphyria. From Sir Walter Raleigh to molecular biology.

The porphyrias are a group of disorders caused by deficient activity of the enzymes responsible for the biosynthesis of haem. The skin is one of the major organs involved in most of these diseases because the porphyrins which accumulate are phototoxic. The common cutaneous porphyrias are variegate porphyria, porphyria cutanea tarda, congenital erythropoietic porphyria and erythropoietic protoporphyria, each caused by a different enzyme deficiency causing a distinctive pattern of porphyrin accumulation and typical clinical features. The genes encoding these enzymes have all been cloned recently, enabling the genetic defects underlying these disorders to be elucidated. The factors triggering sporadic porphyria cutanea tarda in predisposed individuals are now becoming clear: hepatic iron overload is required to induce the hepatic enzyme defect and many patients are haemochromatosis gene carriers. Hepatitis B, C, and HIV virus infection also contribute to disease expression. In erythropoietic protoporphyria, up to 5% of patients develop liver failure. It is now clear that some of these patients suffer from a different recessively transmitted form of the disease: this finding may make it possible to identify these patients at an earlier stage. Gene therapy holds particular promise as a future therapy and has successfully been used to correct enzyme defects in vitro. Bone marrow transplantation has also been tried in patients with congenital erythropoietic porphyria. The joints are not involved by porphyria. However, some non-steroidal inflammatory drugs prescribed by rheumatologists have phototoxic properties similar to uroporphyrin. These drugs cause a syndrome clinically and histologically indistinguishable from porphyria cutanea tarda which is known as pseudoporphyria.

Humans↗
PubMed1998

Telangiectasia macularis eruptiva perstans: a case report and review of the literature.

We report a 20-year-old female patient with telangiectasia macularis eruptiva perstans characterised by telangiectatic macular lesions and episodic flushing, two lesions of which were successfully treated by laser. Two clinically different forms of cutaneous mastocytosis have both been previously described as telangiectasia macularis eruptiva perstans, and we now propose that this term be restricted to cutaneous mastocytosis characterised by the typical telangiectatic macules.

Adult↗
PubMed1998

Protoporphyria.

Human protoporphyria results from mutations in the ferrochelatase gene. Heritable deficiency of ferrochelatase causes overproduction of protoporphyrin IX, principally in the erythron. Photosensitivity is a universal feature of protoporphyria but hepatic clearance of the hydrophobic protoporphyrin molecule with excretion in bile may lead to precipitation within biliary pathways. Thus cholestatic injury and protoporphyrin gallstones occur. Minor hepatic abnormalities are frequent, but at least 30 patients have been reported with a progressive liver disease that requires transplantation. Fulminant hepatic disease appears to be recessively inherited in some pedigrees. Hazards of liver transplantation include tissue photolysis, hemolysis, and an unexplained neurological syndrome, but most of the 15 patients reported after transplantation have survived for several months to > 6 years. Aspects of protoporphyria, its pathogenesis and contemporary therapeutic strategies are considered, with emphasis on hepatic sequelae.

Animals↗
PubMed1995

Autosomal recessive erythropoietic protoporphyria: a syndrome of severe photosensitivity and liver failure.

Erythropoietic protoporphyria is caused by inherited deficiency of the haem synthetic enzyme ferrochelatase, and is characterized by lifelong photosensitivity. About 5% of patients also develop rapidly progressive liver failure. Inheritance is considered to be autosomal dominant, with transmission of a single ferrochelatase defect from one parent. We describe a family in which two siblings with protoporphyria suffered from severe photosensitivity and developed hepatic failure requiring liver transplantation. Their asymptomatic parents were heterozygous for distinct ferrochelatase gene mutations (exon 10 donor site a(+3)-->g and 1088T-->G). Both mutations disrupt splicing of the transcript and cause partial deficiency of ferrochelatase. The affected offspring were compound heterozygotes for these mutations. These patients suffered from an autosomal recessive form of protoporphyria characterized by severe photosensitivity and cholestatic liver disease in adolescence. We postulate that hepatic failure in erythropoietic protoporphyria may in some cases represent an autosomal recessive type of ferrochelatase deficiency distinct from the purely dermatological disorder. Studies of disease inheritance in families affected by protoporphyria may help identify those predisposed to develop severe liver complications, a distinction not currently possible.

Adolescent↗
PubMed1994

Recessive inheritance of erythropoietic protoporphyria with liver failure.

Erythropoietic protoporphyria is characterised by skin photosensitivity and deficiency of ferrochelatase; fatal liver disease occurs rarely. Transmission is considered to be dominant with incomplete penetrance. We investigated a family in which two siblings with erythropoietic protoporphyria developed hepatic failure that required transplantation. Their healthy parents had partial enzyme deficiency and were each heterozygous for a distinct mutation in a ferrochelatase gene. Both offspring were compound heterozygotes with ferrochelatase deficiency. Recessive transmission of protoporphyria predisposes to severe liver disease in this family. Patients with the recessive form of this disease may be at special risk of hepatic failure.

Adolescent↗
PubMed1994

Molecular characterization of a ferrochelatase gene defect causing anomalous RNA splicing in erythropoietic protoporphyria.

Erythropoietic protoporphyria is an inherited disorder caused by deficient activity of the enzyme ferrochelatase. We have examined the ferrochelatase gene in an 11-year-old female with protoporphyria and have found that she is heterozygous for a mutation at a conserved residue in the exon 3 donor splice site consensus sequence (T(+2)-->G). This is inherited from her father, who also has deficient ferrochelatase activity. As a consequence of the mutation, ferrochelatase transcripts are aberrantly spliced and give rise to mRNA molecules in which sequences corresponding to exon 3 are absent. This leads to the expression of a ferrochelatase protein lacking a central region of 40 amino acids.

Base Sequence↗
PubMed1985

Enhancement of the autocatalytic activation of trypsinogen to trypsin by bile and bile acids.

The activation of trypsinogen to trypsin in the small intestine can occur by the action of enterokinase or, alternatively, as an autocatalytic process catalysed by trypsin itself. We have found that bile salts and human bile cause a significant enhancement of the autocatalytic activation of trypsinogen. This effect is dependent on the calcium ion concentration and is most marked around pH 5.4 and 7.8. An optimum concentration exists for each bile salt at which the greatest enhancement occurs. At this concentration, certain bile salts have been shown to produce activation effects of up to 55-fold. It is suggested that this activation of the autocatalytic process by bile plays an important role in protein digestion in the small intestine, since it has been shown previously that duodenal trypsin levels are abnormally low in patients with an impairment of bile secretion.

Bile↗