2-Methylbutyryl-coenzyme A dehydrogenase deficiency: a new inborn error of L-isoleucine metabolism

An 4-mo-old male was found to have an isolated increase in 2-methylbutyrylglycine (2-MBG) and 2-methylbutyrylcamitine (2-MBC) in physiologic fluids. In vitro oxidation studies in cultured fibroblasts using 13C- and 14C-labeled branched chain amino acids indicated an isolated block in 2-methylbutyryl-CoA dehydrogenase (2-MBCDase). Western blotting revealed absence of 2-MBCDase protein in fibroblast extracts; DNA sequencing identified a single 778 C>T substitution in the 2-MBCDase coding region (778 C>T), substituting phenylalanine for leucine at amino acid 222 (L222F) and absence of enzyme activity for the 2-MBCDase protein expressed in Escherichia coli. Prenatal diagnosis in a subsequent pregnancy suggested an affected female fetus, supporting an autosomal recessive mode of inheritance. These data confirm the first documented case of isolated 2-MBCDase deficiency in humans.     

Radioimmunolocalisation in breast cancer using the gene product of c-erbB2 as the target antigen.

Lymph node status is still the single most important prognostic factor in breast cancer. Axillary surgery remains the only reliable means of providing this information. This pilot study evaluates using a highly specific radiolabelled monoclonal antibody to provide equivalent information by a non-invasive technique. After optimisation of labelling conditions, our first antibody, ICR12 (against the gene product of c-erbB-2) was evaluated in a mouse model system. Twenty-four hours post i.v. injection the mice were killed and their organs, blood and tumours harvested for counting. Tumour localisation was four times greater than that into normal tissues, reaching 20% injected dose per gram of tumour. Eight patients have had this Tc99m-ICR12. Patient selection was by immunocytochemical staining of fine needle aspirates from the patient''s own breast cancer. After intravenous administration of the immunoconjugate, tomographic images were obtained at 24 h. These results were compared to the subsequent histopathological examinations. Three patients acted as normal controls, one patient was negative due to inappropriate sampling, and two patients had strong membrane staining and provided excellent tumour localisation to both breast primary and regional node metastases. A further two patients only had moderate antigen expression on staining and did not localise well. The good performance of this radiolabelled antibody with patients that strongly stain for the antigen encourages the development of this system as both a method of staging breast cancer and a potential means of immunotherapy in this subgroup of patients.     

Detecting retinoic acid-induced biochemical alterations in squamous cell carcinoma using intrinsic fluorescence spectroscopys

Intrinsic fluorescence spectroscopy offers a new method for diagnosing head and neck cancers. By establishing a unique spectral fingerprint for benign tissue, one can readily identify subtle changes in tissue based on altered spectral patterns. The authors applied this technology to a multicellular tumor spheroid (MTS) model and obtained baseline spectral data. A cohort of MTS was treated with the chemopreventive agent retinoic acid (RA) to determine its effect on tumor cells. Excitation and emission spectroscopy were performed on the samples. Spectroscopic scans demonstrated consistently that RA-treated MTS exhibit a decrease in the peak associated with reduced nicotinamide-adenine dinucleotide (NADH) and an increase in the peaks associated with flavins, tryptophan, and cytokeratins when compared to controls. These findings are suggestive of alterations in cellular electron transport, an increase in proteins incorporating tryptophan, and a decrease in adenosine triphosphate (ATP) in the RA-treated cells. A discussion of the potential clinical applications of intrinsic fluorescence spectroscopy is included.     

Endonasal laser-assisted dacryocystorhinostomy

Dacryocystorhinostomy is a procedure that is performed to allow drainage of tears from the lacrimal sac directly into the nasal cavity. Endonasal telescopes facilitate performance of this operation with better visualization and decreased morbidity. We present our experience with endoscopic laser-assisted DCR. In the last 31 months, we have performed 31 procedures on 23 patients with either the holmium:YAG laser or the argon:HGM laser. We have a 97% overall success rate with a mean follow-up of 16 months. Our series includes both adult and pediatric patients as well as five revision procedures after failed external DCR. We present our technique, results, and the reasons for our change in laser delivery systems. Most importantly, we discuss the technical factors that contribute to our overall success. These include a large rhinostomy size, simultaneous correction of intranasal and/or sinus pathology, the avoidance of laser use within the lacrimal sac, and close postoperative monitoring with intranasal debridement. We conclude that endoscopic laser-assisted DCR is a better alternative to standard external DCR because it avoids a cutaneous scar, excessive tissue injury, and postoperative morbidity.     

Disseminated mucormycosis: report of a successfully treated immunosuppressed child with clinical,radiographic and pathological findings

Disseminated mucormycosis is an uncommon condition with a high mortality rate and is infrequently diagnosed ante mortem. It is most frequently seen in immunosuppressed patients who are at risk for other unusual infections. The radiological features are not specific. We report the case of a 12-year-old girl in second haematological remission who was successfully treated for a brain abscess due to cerebral mucormycosis and for mucormycosis of the kidney which presented as a pyelonephritis. In her first haematological remission she was diagnosed as having a non-specific pneumonitis, which in retrospect may have been due to mucormycosis. Early diagnosis and appropriate management are associated with improved prognosis and require an awareness of the infection and a high index of suspicion.