ABO blood group antigens in parathyroid adenoma and hyperplasia

Immunohistochemical determination of ABO blood group antigens was performed on parathyroid tissue to see if the presence or absence of such antigens could be used as an aid to distinguish adenoma from hyperplasia in primary hyperparathyroidism. Material from nine cases of solitary adenoma and seven cases of hyperplasia fixed in formalin and embedded in paraffin was studied using monoclonal antibodies and avidin-biotin-peroxidase complex technique. The two categories of tissue did not show any consistent differences in the extent or intensity of immunoreactivity, and the method tested did not permit distinction between adenomatous and hyperplastic disease of the parathyroid glands.     

Fat staining in parathyroid disease—Diagnostic value and impact on surgical strategy: Clinicopathologic analysis of 191 cases

The study comprised 191 cases of surgically treated hyperparathyroidism, with all principal types of parathyroid disease represented. At least two complete glands stained with a modified isopropanol oil red O method for fat, in addition to sections stained with hematoxylin-eosin, were available in each case. On the basis of the morphologic evaluation and the clinical follow-up data, it is concluded that access to two complete glands and the use of fat staining allow highly reliable intraoperative distinction between adenoma and hyperplasia. Of 105 patients followed up for at least one year (mean, 20 months) in whom adenomas were diagnosed, a single possible error was identified. In each of 68 cases classified as hyperplasia on the basis of two abnormal glands, every additional complete gland available (total, 182 glands) was at least partially abnormal, with distinct signs of hyperactivity, irrespective of size. The rate of equivocal findings for cases in which two glands were available (probably adenoma but hyperplasia not excluded) was 8 per cent in 165 cases of primary hyperparathyroidism. These results justify limitation of surgery to one side of the neck in patients in whom adenoma is diagnosed on the basis of a complete, functionally normal (inactive) gland in addition to the presumed adenoma. Thus, the methods described provide a basis for optimal utilization of imaging techniques that allow preoperative localization of parathyroid adenomas.     

Surgical strategy in nonfamilial primary parathyroid hyperplasia: long-term follow-up of thirty-nine cases

The extent and result of surgery in 39 cases of nonfamilial primary parathyroid hyperplasia followed from 2 to 20 years are reported. Thirteen patients had been subjected to subtotal parathyroidectomy leaving no gland intact, while 26 had undergone less extensive surgery leaving at least one grossly normal or near-normal gland intact without biopsy. In the former group two patients (15%) developed permanent hypoparathyroidism requiring vitamin D treatment. In the latter group there were two patients (8%) with persistent hypercalcemia, which might have been avoided with a subtotal parathyroidectomy. Judging from these results, we believe that an individualized surgical approach is justifiable in nonfamilial primary parathyroid hyperplasia. Subtotal parathyroidectomy, leaving no gland intact, is advocated as the method of choice only when all four glands are enlarged. If one or more glands are grossly normal or near normal, factors such as degree of hypercalcemia, symptoms, age, general condition, and life expectancy should be taken into consideration when the extent of the operation is decided. A more conservative operation leaving at least one grossly normal gland intact without biopsy appears to be sufficient for cure in most of these cases and minimizes the risk for development of permanent hypoparathyroidism.     

Metastatic parathyroid carcinoma: dilemmas in management.

The incidence of parathyroid carcinoma in patients surgically treated for primary hyperparathyroidism at the University of Michigan Hospital was 0.4% during an 18-year period. The courses of the five patients with metastatic disease are described. Histologic reevaluation and assessment of the DNA ploidy pattern were performed in each case. Localization studies preceded all reexplorations. The number of operative procedures in each patient ranged from two to 10. Two patients are living with recurrent disease and one has been disease free for 42 months. Two patients died after 2 and 12 years, respectively. Three patients had aneuploid tumors; one had a diploid tumor. One patient had both aneuploid and diploid cell populations. Dilemmas in diagnosis, localization, and medical and surgical management were encountered in patients with metastatic carcinoma. The chosen treatment should be evaluated individually in each case because of the variability in aggressiveness of this malignancy. Surgical resection proved most effective in some of these patients for both local and distant recurrences. Bisphosphonates and gallium nitrate have been reported to be effective in controlling hypercalcemia. Only the former had some effect in one of our patients.     

Oxyphil tumors of the thyroid: follow-up of 42 surgical cases.

Histopathologic and clinical follow-up data on 42 patients observed 2-20 years after operations for oxyphil neoplasms of the thyroid are presented. In eight patients histologic signs of malignancy were found but only two patients showed a clinically malignant course with development of distant metastases. The results do not indicate that oxyphil thyroid neoplasms are especially prone to assume a malignant course with the mode of treatment applied. Our policy is to remove any differentiated epithelial thyroid neoplasm with at least lobectomy. Total thyroidectomy is reserved for cases with capsular penetration, blood vessel invasion and/or metastases.     

Detailed analysis of HTT repeat elements in human blood using targeted amplification‐free long‐read sequencing

Amplification of DNA is required as a mandatory step during library preparation in most targeted sequencing protocols. This can be a critical limitation when targeting regions that are highly repetitive or with extreme guanine–cytosine (GC) content, including repeat expansions associated with human disease. Here, we used an amplification‐free protocol for targeted enrichment utilizing the CRISPR/Cas9 system (No‐Amp Targeted sequencing) in combination with single molecule, real‐time (SMRT) sequencing for studying repeat elements in the huntingtin (HTT) gene, where an expanded CAG repeat is causative for Huntington disease. We also developed a robust data analysis pipeline for repeat element analysis that is independent of alignment of reads to a reference genome. The method was applied to 11 diagnostic blood samples, and for all 22 alleles the resulting CAG repeat count agreed with previous results based on fragment analysis. The amplification‐free protocol also allowed for studying somatic variability of repeat elements in our samples, without the interference of PCR stutter. In summary, with No‐Amp Targeted sequencing in combination with our analysis pipeline, we could accurately study repeat elements that are difficult to investigate using PCR‐based methods.     

Are we moving in the right direction with osteoarthritis drug discovery?

INTRODUCTION: The success of targeted biologic therapy against rheumatoid arthritis has meant that much research has been devoted to investigating the pathophysiology of osteoarthritis, in the hope of defining novel therapeutic targets. Osteoarthritis has long been thought of mainly as a degenerative disease of cartilage, with secondary bony damage and osteophytes. However, in recent years, the importance of the synovium, and in particular the synovial macrophages, has been highlighted in both in vitro and in vivo studies. AREAS COVERED: The recent progress in osteoarthritis drug discovery, particularly with regard to the search for therapeutic targets for this disease and the development of disease-modifying anti-osteoarthritic drugs is critically assessed. Some important recent research with regard to possible therapeutic targets in osteoarthritis drug discovery is highlighted. EXPERT OPINION: The concept that synovial macrophages and macrophage-produced cytokines, may play a role in driving inflammatory and destructive signalling pathways in osteoarthritis, is of importance for drug discovery in this disease, in spite of disappointing results from early studies of anti-cytokine strategies in osteoarthritis clinical trials. There is also an abundance of potential downstream therapeutic targets in osteoarthritis, including the matrix metalloproteinases, the aggrecanases, iNOS and elements of the Wnt pathway.     

Candidate Gene Association Study for Noise-induced Hearing Loss in Two Independent Noise-exposed Populations

Millions of people are daily exposed to high levels of noise. Consequently, noise-induced hearing loss (NIHL) is one of the most important occupational health hazards worldwide. In this study, we performed an association study for NIHL based on a candidate gene approach. 644 Single Nucleotide Polymorphisms (SNPs) in 53 candidate genes were analyzed in two independent NIHL sample sets, a Swedish set and part of a Polish set. Eight SNPs with promising results were selected and analysed in the remaining part of the Polish samples. One SNP in PCDH15 (rs7095441), resulted in significant associations in both sample sets while two SNPs in MYH14 (rs667907 and rs588035), resulted in significant associations in the Polish sample set and significant interactions with noise exposure level in the Swedish sample set. Calculation of odds ratios revealed a significant association of rs588035 with NIHL in the Swedish high noise exposure level group. Our studies suggest that PCDH15 and MYH14 may be NIHL susceptibility genes, but further replication in independent sample sets is mandatory.     

Noonan syndrome and neurofibromatosis type I in a family with a novel mutation in NF1

Noonan syndrome (NS) and neurofibromatosis type I (NF1) belong to a group of clinically related disorders that share a common pathogenesis, dysregulation of the RAS‐MAPK pathway. NS is characterized by short stature, heart defect, pectus deformity and facial dysmorphism, whereas skin manifestations, skeletal defects, Lisch nodules and neurofibromas are characteristic of NF1. Both disorders display considerable clinical variability. Features of NS have been observed in individuals with NF1 –a condition known as neurofibromatosis–Noonan syndrome (NFNS). The major gene causing NFNS is NF1. Rarely, a mutation in PTPN11 in addition to an NF1 mutation is present. We present the clinical and molecular characterization of a family displaying features of both NS and NF1, with complete absence of neurofibromas. To investigate the etiology of the phenotype, mutational analysis of NF1 was conducted, revealing a novel missense mutation in exon 24, p.L1390F, affecting the GAP‐domain. Additional RAS‐MAPK pathway genes were examined, but no additional mutations were identified. We confirm that NF1 mutations are involved in the etiology of NFNS. Furthermore, based on our results and previous studies we suggest that evaluation of the GAP‐domain of NF1 should be prioritized in NFNS.     

Variations in HSP70 genes associated with noise-induced hearing loss in two independent populations

Noise-induced hearing loss (NIHL) is one of the most important occupational health hazards. Millions of people worldwide are exposed daily to harmful levels of noise. NIHL is a complex disease resulting from an interaction between genetic and environmental factors. Although the environmental risk factors have been studied extensively, little is known about the genetic factors. Heat-shock proteins (HSPs) are induced after exposure to severe noise. When first induced by exposure to moderate sound levels, they can protect the ear from damage from excessive noise exposure. This protection is highly variable between individuals. An association of HSP70 genes with NIHL has been described by Yang et al (2006) in a Chinese sample set of noise-exposed workers. In this study, three polymorphisms (rs1043618, rs1061581 and rs2227956) in HSP70-1, HSP70-2 and HSP70-hom, respectively, were genotyped in 206 Swedish and 238 Polish DNA samples of noise-exposed subjects and analyzed. One SNP, rs2227956 in HSP70-hom, resulted in a significant association with NIHL in both sample sets. In addition, rs1043618 and rs1061581 were significant in the Swedish sample set. Analysis of the haplotypes composed of the three SNPs revealed significant associations between NIHL and haplotype GAC in both sample sets and with haplotype CGT in the Swedish sample set. In conclusion, this study replicated the association of HSP70 genes with NIHL in a second and third independent noise-exposed sample set, hereby adding to the evidence that HSP70 genes may be NIHL susceptibility genes.