Reactivation of heat-inactivated Ku proteins by heat shock cognate protein HSC73

Purpose: Mouse double-stranded DNA-dependent protein kinase (DNA-PK) activity is heat sensitive. Recovery of heat-inactivated DNA repair activity is a problem after combination therapy with radiation and heat. We investigated the mechanism of recovery of heat-inactivated DNA-PK activity.

Methods: Hybrid cells containing a fragment of human chromosome 8 in scid cells (RD13B2) were used. DNA-PK activity was measured by an in vitro assay. Immunoprecipitation of the nuclear extract was performed with an anti-Ku80 antibody. Proteins co-precipitated with Ku80 were separated by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis and detected by Western blotting using anti-heat shock protein (HSP)72 and anti-heat shock cognate protein (HSC)73 antibodies. HSC73 was overexpressed with the pcDNA3.1 vector. Short hairpin (sh)RNA was used to downregulate HSC73 and HSP72.

Results: The activity of heat-inactivated DNA-PK recovered to about 50% of control during an additional incubation at 37?°C after heat treatment at 44?°C for 15?min in the presence of cycloheximide (which inhibits de novo protein synthesis). Maximal recovery was observed within 3?h of incubation at 37?°C after heat treatment. Constitutively expressed HSC73, which folds newly synthesized proteins, reached maximal levels 3?h after heat treatment using a co-immunoprecipitation assay with the Ku80 protein. Inhibiting HSC73, but not HSP72, expression with shRNA decreased the recovery of DNA-PK activity after heat treatment.

Conclusions: These results suggest that de novo protein synthesis is unnecessary for recovery of some heat-inactivated DNA-PK. Rather, it might be reactivated by the molecular chaperone activity of HSC73, but not HSP72.     

beta2- and beta3-Adrenoceptor polymorphisms relate to subsequent weight gain and blood pressure elevation in obese normotensive individuals.

High blood pressure (BP) is a major determinant of cardiovascular events in obesity. The beta2- and beta3-adrenoceptor polymorphisms are associated with obesity and hypertension. In the present study, we examine the relationships of beta2- and beta3-adrenoceptor polymorphisms with further weight gain-induced BP elevation in obese subjects. Changes in BP, body weight, total body fat-mass, waist-to-hip ratio, plasma norepinephrine (NE) and leptin levels, and beta2(Arg16Gly)- and beta3(Trp64Arg)-adrenoceptor polymorphisms were measured periodically over a 5-year period in 55 entry obese (body mass index [BMI]> or =25.0 kg/m(2)) normotensive (BP<140/90 mmHg) men. BP elevation and weight gain were defined as > or =10% increases from entry levels over 5 years in mean BP or BMI. Obese subjects with weight gain, BP elevation or weight gain-induced BP elevation had higher frequencies of the Gly16 allele of Arg16GIy and Arg64 allele of Trp64Arg. Subjects carrying the Gly16 or Arg64 alleles had significantly greater total fat-mass and waist-to-hip ratio at entry and over a 5-year period compared to the subjects who did not carry these polymorphisms. Subjects carrying the Gly16 allele had similar levels of plasma NE, higher levels of plasma leptin and a lower slope of the regression lines between plasma leptin and NE levels. Those carrying the Arg64 allele had higher plasma NE levels at entry and over a 5-year period compared to the subjects without the Arg64 allele, but plasma leptin levels and slopes were similar. The findings demonstrate that the Arg64 allele of the beta3-adrenoceptor polymorphisms relates to weight gain-induced BP elevation accompanying high plasma NE (heightened sympathetic activity) in obese men. The Gly16 allele of the beta2-adrenoceptor polymorphisms links to weight gain-induced BP elevation associated with leptin resistance. beta2- and beta3-adrenoceptor polymorphisms could predict the future BP elevation and further weight gain-induced BP elevation in originally obese subjects.     

Kindling of the visual cortex in cats: comparison with amygdaloid kindling

Kindling of the primary visual cortex (VC) was compared with that of the amygdala in cats. VC kindling was basically similar to kindling of the amygdala in that daily electrical stimulation can lead to the development of a generalized convulsion in most subjects, a growth of afterdischarges in their configuration and duration, and a reduction of the afterdischarge threshold. The kindling response of the VC differed from that of the amygdala in a number of respects, i.e., a high afterdischarge threshold, a different pattern of behavioral seizure development, an abrupt growth of electroclinical seizures coincident with the onset of a generalized convulsion, an intersubject variability in seizure susceptibility, and a marked seizure instability. In VC kindling the afterdischarge propagation into the amygdala was not observed until the generalized convulsion developed, and the early involvement of afterdischarge was seen in the pulvinar, lateral geniculate body, and superior colliculus. These data suggest that a neural mechanism different from amygdaloid kindling may participate in VC kindling, and that the subcortical structures of the visual system are involved in the preferential pathway for a seizure generalization from the VC.     

Surgical outcomes of partial nephrectomy for renal cell carcinoma: A joint study by the Japanese Society of Renal Cancer

OBJECTIVE: A joint study was undertaken by the Japanese Society of Renal Cancer to investigate the present status of partial nephrectomy in Japan and to speculate about what may be the indications for partial nephrectomy in patients with renal cell carcinoma. METHODS: Data were tabulated for 469 patients from participating medical institutions and various clinical factors were investigated with regard to disease progression (local recurrence and distant metastasis). RESULTS: Disease progression was observed in 21 patients (4.5%). No significant relation to disease progression was observed for sex, laterality, tumor histology, grade and tumor size. Although patients with solitary tumors displayed excellent prognosis irrespective of tumor diameter, patients with multiple tumors displayed a high likelihood of disease progression. Patients older than 77 years old and patients with imperative indication were found to have a poorer prognosis. CONCLUSION: In patients with solitary tumors, partial nephrectomy can be actively performed, even if the patient displays elective indications and the tumor is >4 cm in diameter. In patients displaying multiple tumors with imperative indications, the decision whether to perform partial nephrectomy should be made by the patients and their physicians after considering the impact on curability and the quality of life.     

Early onset of ganciclovir-resistant cytomegalovirus infection in a lung-transplant recipient.

Ganciclovir resistance in cytomegalovirus (CMV) is an increasing problem in lung-transplant recipients with adverse clinical outcomes. We experienced the successful treatment of ganciclovir-resistant CMV infection in a lung-transplant recipient still receiving CMV prophylaxis. A 24-year-old woman with lymphangioleiomyomatosis underwent a living-donor lobar lung transplantation. She was a primary CMV mismatch (D+/R-) patient. She recovered from her postoperative complications, and was about to be discharged. However, she suffered ganciclovir-resistant CMV infection during prophylactic therapy. She was successfully treated with foscarnet, and is now alive without recurrence 18 months after surgery.     

The enhanced expression of the matrix metalloproteinase 9 in nasal NK/T-cell lymphoma

Background  

Nasal NK/T cell lymphoma is an aggressive disease and has a poor prognosis. Nasal NK/T cell lymphoma is refractory to conventional chemotherapy and has strong tendency of widespread relapse or dissemination into distant sites.     

Resected cases of middle lobe primary cancer

Of 200 lung cancer lesions resected in our hospital, there were 15 cases (7.5%) with middle lobe origin. The histological types were adenocarcinoma in 13 patients (4 patients with alveolar cell carcinoma), squamous cell carcinoma in one and large cell carcinoma in one. These patients were classified into two groups according to the type of operation they received and each group was evaluated. Group I (resection of the middle lobe) included 8 patients. Each one of Stage IIIB and Stage IV received the operation to improve their symptoms. The six patients of Stage I received only middle lobectomy as absolute curable cases. Group II (resection of the middle and lower lobes) included 7 patients, who had preoperative diagnosis of stage III. Two of them were postoperatively found to be cases of Stage I and Stage II. Although it was still short-term, the follow-up evaluation proved that these patients survived without local recurrence and distant metastasis, except for two with pleural dissemination and one with cerebral metastasis, who had received lobectomy as palliative operation. No difference was observed between the two groups receiving different types of operation.     

The results and problems of reoperation for coronary artery disease]

In six hundred and six consecutive patients undergoing coronary artery bypass grafting (CABG) within the past 17 years (May 1974 to March 1991), repeated CABG were performed on 10 patients (1.65%). The main reasons for repeated CABG were graft failure (GF) in 8, progression of native disease (NP) in 5 and incomplete revascularization (IR) in 3 patients. The incidence of GF was high either within a half year or around 5 years after CABG. Although all patients survived from reoperation, four patients continued to have mild angina pectoris. When the recurrence of angina is noted after CABG, coronary arteriography and if necessary PTCA should be done as soon as possible. If a second surgery is inevitable, maximum utilization of arterial graft and accomplishment of complete revascularization are emphasized.